diff --git a/.gitignore b/.gitignore
index fd29596..c099e65 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,8 @@
 # OS X
 .DS_Store
+
+# Generated documentation
+docs/
+
+# Local settings
+*.local.php
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..afa0e30
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,4 @@
+.PHONY: docs
+
+docs:
+	phpdoc -d Splunk -t docs
diff --git a/README.md b/README.md
index 9282e49..8994a43 100644
--- a/README.md
+++ b/README.md
@@ -51,7 +51,7 @@ into the repository with git:
 
 ## Requirements
 
-The SDK requires PHP 5.3+
+The SDK requires PHP 5.2+
 
 ## ...
 
diff --git a/Splunk.php b/Splunk.php
new file mode 100644
index 0000000..ffa3105
--- /dev/null
+++ b/Splunk.php
@@ -0,0 +1,30 @@
+<?php
+/**
+ * Copyright 2012 Splunk, Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"): you may
+ * not use this file except in compliance with the License. You may obtain
+ * a copy of the License at
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+
+/**
+ * Intercepts failed attempts to load classes of the form 'Splunk_*'
+ * and automatically includes the appropriate PHP file for the class.
+ */
+function Splunk_autoload($className)
+{
+    if (substr_compare($className, 'Splunk_', 0, strlen('Splunk_')) != 0)
+        return false;
+    $file = str_replace('_', '/', $className);
+    return include dirname(__FILE__) . "/$file.php";
+}
+
+spl_autoload_register('Splunk_autoload');
diff --git a/Splunk/Context.php b/Splunk/Context.php
new file mode 100644
index 0000000..c554093
--- /dev/null
+++ b/Splunk/Context.php
@@ -0,0 +1,99 @@
+<?php
+/**
+ * Copyright 2012 Splunk, Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"): you may
+ * not use this file except in compliance with the License. You may obtain
+ * a copy of the License at
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+
+/**
+ * This class allows clients to issue HTTP requests to a Splunk server.
+ * 
+ * @package Splunk
+ */
+class Splunk_Context
+{
+    private $username;
+    private $password;
+    private $host;
+    private $port;
+    private $scheme;
+    private $http;
+    
+    private $token;
+    
+    /**
+     * @param array $args {
+     *      'username' => (optional) The username to login with. Defaults to "admin".
+     *      'password' => (optional) The password to login with. Defaults to "changeme".
+     *      'host' => (optional) The hostname of the Splunk server. Defaults to "localhost".
+     *      'port' => (optional) The port of the Splunk server. Defaults to 8089.
+     *      'scheme' => (optional) The scheme to use: either "http" or "https". Defaults to "https".
+     *      'http' => (optional) An Http object that will be used for performing HTTP requests.
+     * }
+     */
+    public function __construct($args)
+    {
+        $args = array_merge(array(
+            'username' => 'admin',
+            'password' => 'changeme',
+            'host' => 'localhost',
+            'port' => 8089,
+            'scheme' => 'https',
+            'http' => new Splunk_Http(),
+        ), $args);
+        
+        $this->username = $args['username'];
+        $this->password = $args['password'];
+        $this->host = $args['host'];
+        $this->port = $args['port'];
+        $this->scheme = $args['scheme'];
+        $this->http = $args['http'];
+    }
+    
+    // === Operations ===
+    
+    /**
+     * Authenticates to the Splunk server.
+     */
+    public function login()
+    {
+        $response = $this->http->post($this->url('/services/auth/login'), array(
+            'username' => $this->username,
+            'password' => $this->password,
+        ));
+        
+        $sessionKey = Splunk_Util::getTextContentAtXpath(
+            new SimpleXMLElement($response['body']),
+            '/response/sessionKey');
+        
+        $this->token = 'Splunk ' . $sessionKey;
+    }
+    
+    // === Accessors ===
+    
+    /**
+     * Returns the token used to authenticate HTTP requests
+     * after logging in.
+     */
+    public function getToken()
+    {
+        return $this->token;
+    }
+    
+    // === Utility ===
+    
+    private function url($path)
+    {
+        return "{$this->scheme}://{$this->host}:{$this->port}{$path}";
+    }
+}
diff --git a/Splunk/Http.php b/Splunk/Http.php
new file mode 100644
index 0000000..182c060
--- /dev/null
+++ b/Splunk/Http.php
@@ -0,0 +1,154 @@
+<?php
+/**
+ * Copyright 2012 Splunk, Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"): you may
+ * not use this file except in compliance with the License. You may obtain
+ * a copy of the License at
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+
+/**
+ * HTTP abstraction layer.
+ * 
+ * @package Splunk
+ */
+class Splunk_Http
+{
+    public function get($url)
+    {
+        return $this->request('get', $url);
+    }
+    
+    public function post($url, $params=array())
+    {
+        return $this->request('post', $url, http_build_query($params));
+    }
+    
+    /**
+     * @param string $method        HTTP request method (ex: 'get').
+     * @param string $url           URL to fetch.
+     * @param string $request_body  content to send in the request.
+     * @return object {
+     *      'status' => HTTP status code (ex: 200).
+     *      'reason' => HTTP reason string (ex: 'OK').
+     *      'headers' => Dictionary of headers. (ex: array('Content-Length' => '0')).
+     *      'body' => Content of the response.
+     * }
+     */
+    private function request($method, $url, $request_body='')
+    {
+        $opts = array(
+            CURLOPT_HTTPGET => TRUE,
+            CURLOPT_URL => $url,
+            CURLOPT_TIMEOUT => 60,  // secs
+            CURLOPT_RETURNTRANSFER => TRUE,
+            CURLOPT_HEADER => TRUE,
+            // disable SSL certificate validation
+            CURLOPT_SSL_VERIFYPEER => FALSE,
+        );
+        
+        switch ($method)
+        {
+            case 'get':
+                $opts[CURLOPT_HTTPGET] = TRUE;
+                break;
+            case 'post':
+                $opts[CURLOPT_POST] = TRUE;
+                $opts[CURLOPT_POSTFIELDS] = $request_body;
+                break;
+            default:
+                $opts[CURLOPT_CUSTOMREQUEST] = strtoupper($method);
+                break;
+        }
+        
+        if (!($curl = curl_init()))
+            throw new Splunk_ConnectException('Unable to initialize cURL.');
+        if (!(curl_setopt_array($curl, $opts)))
+            throw new Splunk_ConnectException(curl_error($curl));
+        if (!($response = curl_exec($curl)))
+            throw new Splunk_ConnectException(curl_error($curl));
+        
+        $status = curl_getinfo($curl, CURLINFO_HTTP_CODE);
+        
+        $header_size = curl_getinfo($curl, CURLINFO_HEADER_SIZE);
+        $header_text = substr($response, 0, $header_size);
+        $body = substr($response, $header_size);
+        
+        $headers = array();
+        $header_lines = explode("\r\n", trim($header_text));
+        $status_line = array_shift($header_lines);
+        foreach ($header_lines as $line)
+        {
+            list($key, $value) = explode(':', $line, 2);
+            $headers[$key] = trim($value);
+        }
+        
+        list($http_version, $_, $reason) = explode(' ', $status_line, 3);
+        
+        $response = array(
+            'status' => $status,
+            'reason' => $reason,
+            'headers' => $headers,
+            'body' => $body,
+        );
+        
+        if ($status >= 400)
+            throw new Splunk_HttpException($response);
+        else
+            return $response;
+    }
+}
+
+/**
+ * Thrown when unable to connect to a Splunk server.
+ * 
+ * @package Splunk
+ */
+class Splunk_ConnectException extends Exception {}
+
+/**
+ * Thrown when an HTTP request fails due to a non 2xx status code.
+ * 
+ * @package Splunk
+ */
+class Splunk_HttpException extends Exception
+{
+    private $response;
+    
+    // === Init ===
+    
+    public function __construct($response)
+    {
+        $detail = Splunk_HttpException::parseFirstMessageFrom($response);
+        
+        // FIXME: Include HTTP "reason" in message
+        $message = "HTTP {$response['status']} {$response['reason']}";
+        if ($detail != NULL)
+            $message .= ' -- ' . $detail;
+        
+        $this->response = $response;
+        parent::__construct($message);
+    }
+    
+    private static function parseFirstMessageFrom($response)
+    {
+        return Splunk_Util::getTextContentAtXpath(
+            new SimpleXMLElement($response['body']),
+            '/response/messages/msg');
+    }
+    
+    // === Accessors ===
+    
+    public function getResponse()
+    {
+        return $this->response;
+    }
+}
diff --git a/Splunk/Util.php b/Splunk/Util.php
new file mode 100644
index 0000000..afdac71
--- /dev/null
+++ b/Splunk/Util.php
@@ -0,0 +1,48 @@
+<?php
+/**
+ * Copyright 2012 Splunk, Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"): you may
+ * not use this file except in compliance with the License. You may obtain
+ * a copy of the License at
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+
+/**
+ * Internal utilities used by the Splunk package.
+ * 
+ * @package Splunk
+ */
+class Splunk_Util
+{
+    /**
+     * @param SimpleXMLElement  $xmlElement
+     * @param string            $xpathExpr
+     * @return string|NULL
+     */
+    public static function getTextContentAtXpath($xmlElement, $xpathExpr)
+    {
+        $matchingElements = $xmlElement->xpath($xpathExpr);
+        return (count($matchingElements) == 0)
+            ? NULL
+            : Splunk_Util::getTextContentOfXmlElement($matchingElements[0]);
+    }
+    
+    /**
+     * @param SimpleXMLElement $xmlElement
+     * @return string
+     */
+    private static function getTextContentOfXmlElement($xmlElement)
+    {
+        // HACK: Some versions of PHP 5 can't access the [0] element
+        //       of a SimpleXMLElement object properly.
+        return (string) $xmlElement;
+    }
+}
diff --git a/tests/ContextTest.php b/tests/ContextTest.php
new file mode 100644
index 0000000..4d71ccf
--- /dev/null
+++ b/tests/ContextTest.php
@@ -0,0 +1,85 @@
+<?php
+/**
+ * Copyright 2012 Splunk, Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"): you may
+ * not use this file except in compliance with the License. You may obtain
+ * a copy of the License at
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+
+require_once '../Splunk.php';
+require_once 'settings.php';
+
+class ContextTest extends PHPUnit_Framework_TestCase
+{
+    public function testLoginSuccess()
+    {
+        $http_response = array(
+            'status' => 200,
+            'reason' => 'OK',
+            'headers' => array(),
+            'body' => '
+<response>
+<sessionKey>068b3021210eb4b67819b1a292302948</sessionKey>
+</response>');
+        
+        $http = $this->getMock('Splunk_Http');
+        $http->expects($this->once())
+             ->method('post')
+             ->will($this->returnValue($http_response));
+        
+        $context = new Splunk_Context(array(
+            'http' => $http,
+        ));
+        $context->login();
+        
+        $this->assertEquals(
+            'Splunk 068b3021210eb4b67819b1a292302948',
+            $context->getToken());
+    }
+    
+    /**
+     * @expectedException           Splunk_HttpException
+     * @expectedExceptionMessage    Login failed
+     */
+    public function testLoginFailDueToBadPassword()
+    {
+        $http_response = array(
+            'status' => 401,
+            'reason' => 'Unauthorized',
+            'headers' => array(),
+            'body' => '
+<response>
+<messages>
+<msg type="WARN">Login failed</msg>
+</messages>
+</response>');
+        
+        $http = $this->getMock('Splunk_Http');
+        $http->expects($this->once())
+             ->method('post')
+             ->will($this->throwException(
+                new Splunk_HttpException($http_response)));
+        
+        $context = new Splunk_Context(array(
+            'http' => $http,
+        ));
+        $context->login();
+    }
+    
+    public function testLoginSuccessOnRealServer()
+    {
+        global $Splunk_testSettings;
+        
+        $context = new Splunk_Context($Splunk_testSettings['connectArgs']);
+        $context->login();
+    }
+}
diff --git a/tests/HttpTest.php b/tests/HttpTest.php
new file mode 100644
index 0000000..4966c8b
--- /dev/null
+++ b/tests/HttpTest.php
@@ -0,0 +1,30 @@
+<?php
+/**
+ * Copyright 2012 Splunk, Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"): you may
+ * not use this file except in compliance with the License. You may obtain
+ * a copy of the License at
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+
+require_once '../Splunk.php';
+
+class HttpTest extends PHPUnit_Framework_TestCase
+{
+    public function testGet()
+    {
+        $http = new Splunk_Http();
+        $response = $http->get('http://www.splunk.com/');
+        
+        $this->assertEquals(200, $response['status']);
+        $this->assertContains('<head>', $response['body']);
+    }
+}
diff --git a/tests/Makefile b/tests/Makefile
new file mode 100644
index 0000000..4db1caa
--- /dev/null
+++ b/tests/Makefile
@@ -0,0 +1,2 @@
+test:
+	phpunit .
diff --git a/tests/README.md b/tests/README.md
new file mode 100644
index 0000000..6603513
--- /dev/null
+++ b/tests/README.md
@@ -0,0 +1,13 @@
+## Requirements
+
+* PHPUnit 3.6
+
+## Running the Tests
+
+Navigate to this directory, then run:
+
+    phpunit .
+
+Or alternatively:
+
+    make
\ No newline at end of file
diff --git a/tests/settings.default.php b/tests/settings.default.php
new file mode 100644
index 0000000..83c31a4
--- /dev/null
+++ b/tests/settings.default.php
@@ -0,0 +1,13 @@
+<?php
+
+/*
+ * Configuration for unit tests.
+ */
+
+// Credentials to connect to a test instance of Splunk
+$Splunk_testSettings['connectArgs'] = array(
+    //'host' => 'localhost',
+    //'port' => 8089,
+    //'username' => 'admin',
+    'password' => 'changeme',
+);
diff --git a/tests/settings.php b/tests/settings.php
new file mode 100644
index 0000000..a6f9caa
--- /dev/null
+++ b/tests/settings.php
@@ -0,0 +1,4 @@
+<?php
+
+require 'settings.default.php';
+include 'settings.local.php';   // warn if file not found