Create the Request method.
diff --git a/provider_client.go b/provider_client.go
index 7754c20..618a0ef 100644
--- a/provider_client.go
+++ b/provider_client.go
@@ -1,5 +1,14 @@
 package gophercloud
 
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net/http"
+)
+
 // ProviderClient stores details that are required to interact with any
 // services within a specific provider's API.
 //
@@ -24,10 +33,154 @@
 	// EndpointLocator describes how this provider discovers the endpoints for
 	// its constituent services.
 	EndpointLocator EndpointLocator
+
+	// HTTPClient allows users to interject arbitrary http, https, or other transit behaviors.
+	HTTPClient http.Client
 }
 
 // AuthenticatedHeaders returns a map of HTTP headers that are common for all
 // authenticated service requests.
 func (client *ProviderClient) AuthenticatedHeaders() map[string]string {
+	if client.TokenID == "" {
+		return map[string]string{}
+	}
 	return map[string]string{"X-Auth-Token": client.TokenID}
 }
+
+// RequestOpts customizes the behavior of the provider.Request() method.
+type RequestOpts struct {
+	// JSONBody, if provided, will be encoded as JSON and used as the body of the HTTP request. The
+	// content type of the request will default to "application/json" unless overridden by MoreHeaders.
+	// It's an error to specify both a JSONBody and a RawBody.
+	JSONBody interface{}
+	// RawBody contains an io.Reader that will be consumed by the request directly. No content-type
+	// will be set unless one is provided explicitly by MoreHeaders.
+	RawBody io.Reader
+
+	// JSONResponse, if provided, will be populated with the contents of the response body parsed as
+	// JSON.
+	JSONResponse *interface{}
+	// OkCodes contains a list of numeric HTTP status codes that should be interpreted as success. If
+	// the response has a different code, an error will be returned.
+	OkCodes []int
+
+	// MoreHeaders specifies additional HTTP headers to be provide on the request. If a header is
+	// provided with a blank value (""), that header will be *omitted* instead: use this to suppress
+	// the default Accept header or an inferred Content-Type, for example.
+	MoreHeaders map[string]string
+}
+
+// UnexpectedResponseCodeError is returned by the Request method when a response code other than
+// those listed in OkCodes is encountered.
+type UnexpectedResponseCodeError struct {
+	URL      string
+	Method   string
+	Expected []int
+	Actual   int
+	Body     []byte
+}
+
+func (err *UnexpectedResponseCodeError) Error() string {
+	return fmt.Sprintf(
+		"Expected HTTP response code %v when accessing [%s %s], but got %d instead\n%s",
+		err.Expected, err.Method, err.URL, err.Actual, err.Body,
+	)
+}
+
+var applicationJSON = "application/json"
+
+// Request performs an HTTP request using the ProviderClient's current HTTPClient. An authentication
+// header will automatically be provided.
+func (client *ProviderClient) Request(method, url string, options RequestOpts) (*http.Response, error) {
+	var body io.Reader
+	var contentType *string
+
+	// Derive the content body by either encoding an arbitrary object as JSON, or by taking a provided
+	// io.Reader as-is. Default the content-type to application/json.
+
+	if options.JSONBody != nil {
+		if options.RawBody != nil {
+			panic("Please provide only one of JSONBody or RawBody to gophercloud.Request().")
+		}
+
+		rendered, err := json.Marshal(options.JSONBody)
+		if err != nil {
+			return nil, err
+		}
+
+		body = bytes.NewReader(rendered)
+		contentType = &applicationJSON
+	}
+
+	if options.RawBody != nil {
+		body = options.RawBody
+	}
+
+	// Construct the http.Request.
+
+	req, err := http.NewRequest(method, url, body)
+	if err != nil {
+		return nil, err
+	}
+
+	// Populate the request headers. Apply options.MoreHeaders last, to give the caller the chance to
+	// modify or omit any header.
+
+	if contentType != nil {
+		req.Header.Add("Content-Type", *contentType)
+	}
+	req.Header.Add("Accept", applicationJSON)
+
+	for k, v := range client.AuthenticatedHeaders() {
+		req.Header.Add(k, v)
+	}
+
+	if options.MoreHeaders != nil {
+		for k, v := range options.MoreHeaders {
+			if v != "" {
+				req.Header.Add(k, v)
+			} else {
+				req.Header.Del(k)
+			}
+		}
+	}
+
+	// Issue the request.
+
+	resp, err := client.HTTPClient.Do(req)
+	if err != nil {
+		return nil, err
+	}
+
+	// Validate the response code, if requested to do so.
+
+	if options.OkCodes != nil {
+		var ok bool
+		for _, code := range options.OkCodes {
+			if resp.StatusCode == code {
+				ok = true
+				break
+			}
+		}
+		if !ok {
+			body, _ := ioutil.ReadAll(resp.Body)
+			resp.Body.Close()
+			return resp, &UnexpectedResponseCodeError{
+				URL:      url,
+				Method:   method,
+				Expected: options.OkCodes,
+				Actual:   resp.StatusCode,
+				Body:     body,
+			}
+		}
+	}
+
+	// Parse the response body as JSON, if requested to do so.
+
+	if options.JSONResponse != nil {
+		defer resp.Body.Close()
+		json.NewDecoder(resp.Body).Decode(options.JSONResponse)
+	}
+
+	return resp, nil
+}