If you have little or no existing experience with Windows Forms and want to pass the exam, this is a good place to start learning.
But if you already have experience with Windows Forms, you might be disappointed...
This is effectively a second edition of the book that covered the Windows Forms 2.0 exam (70-526). It seems as though 95% of the content is identical, so I do *not* recommend buying this edition if you already have the 2.0 book.
The authors have only added content for two new topics: 24 pages on LINQ and 3 pages on hosting a WPF control by using ElementHost. But they have missed out some important deployment-related topics that appear on the exam:
1) Install a Windows Presentation Foundation (WPF) browser application by using ClickOnce
2) Install a Visual Studio Tools for Office (VSTO) application by using ClickOnce
3) Configure and work with Windows Vista User Account Control (UAC) by using ClickOnce deployments
4) Set appropriate security permissions to deploy the application. This objective may include but is not limited to: elevated permissions
5) Configure Trusted Application deployments
6) Configure security features in an application. This objective may include but is not limited to: Configure code access security, configure the application to work with UAC, configure Windows manipulation permissions, configure appropriate file access permissions for the application, control printing security for the application
So if you have the previous book or you're already experienced with Windows Forms 2.0 then you're better off simply reading Microsoft's free MSDN site. In particular, read the topic titled "What's New in Windows Forms for the .NET Framework 3.5" in combination with Microsoft's official preparation guide for the exam. I wish the authors had!