As Jon Flanders explains early on in his enjoyable book, <i>RESTful .NET</i>, Representational State Transfer (REST) is a set of guidelines on how to architect your web applications. Because it is tightly aligned with HTTP, architectures that follow the principles of REST are able to hook into a number of benefits that come built into the technologies that surround the web.
Flanders delves into REST briefly, but he does it well enough that you understand its value even if you haven't consumed the groundbreaking book RESTful Web Services.
The transition to programming REST using .NET is just as nicely handled. Windows Communication Foundation is a sprawling technology precisely because it is a model that covers a wide variety of programming paradigms (it supports a multitude of protocols like messaging, HTTP, SOAP, etc).
There is a quick tutorial on implementing HTTP services using WCF - which serves to remind us that WCF isn't only tightly coupled to SOAP. The rest of the book is divided up into chapters that zero in on specific implementation using WCF: Read-only services, Read/Write services, RESTful services and Feeds. Flanders also covers both server side implementation and client-side consumption of the services. There is coverage of Ajax and Silverlight clients and a short chapter on using WCF Workflow to deliver the REST services.
RESTful .NET's biggest strength is that it is concise, clear and lean. It zeroes in on the essentials and provides very lean tutorials.
To that point, you need the basics of HTTP, SOAP, WCF, XML, C# and (briefly) ASP in place to fully appreciate the book. The most valuable chapter for me was the one in which Flanders covers programming feeds. But there is enough diversity in terms of types of constructs implemented, that you'll find something of value here.
It is highly recommended if you are a Windows Web programmer and have a growing interest in REST.