diff --git a/context.go b/context.go
index 28cb5f9..70d70a7 100644
--- a/context.go
+++ b/context.go
@@ -4,21 +4,34 @@
 	"net/http"
 )
 
+// Context structures encapsulate Gophercloud-global state in a manner which
+// facilitates easier unit testing.  As a user of this SDK, you'll never
+// have to use this structure, except when contributing new code to the SDK.
 type Context struct {
 	// providerMap serves as a directory of supported providers.
-	providerMap map[string]*Provider
+	providerMap map[string]Provider
 
 	// httpClient refers to the current HTTP client interface to use.
 	httpClient *http.Client
 }
 
+// TestContext yields a new Context instance, pre-initialized with a barren
+// state suitable for per-unit-test customization.  This configuration consists
+// of:
+//
+// * An empty provider map.
+//
+// * An HTTP client built by the net/http package (see http://godoc.org/net/http#Client).
 func TestContext() *Context {
 	return &Context{
-		providerMap: make(map[string]*Provider),
+		providerMap: make(map[string]Provider),
 		httpClient:  &http.Client{},
 	}
 }
 
+// UseCustomClient configures the context to use a customized HTTP client
+// instance.  By default, TestContext() will return a Context which uses
+// the net/http package's default client instance.  
 func (c *Context) UseCustomClient(hc *http.Client) {
 	c.httpClient = hc
 }