Charles Petzold is one of the greatest authors of programming books; if you're a Windows programmer this is not news. I've read many of his books and I always think of them as the best books to explain the core concepts our applications build on. He's not limited to programming books, Code is a great book for anyone involved with computers - at any level.
Charles has just published his latest book, Applications = Code + Markup which is an introduction to WPF and .NET 3.0 (Vista) programming. When he started this book, he began a "chapter zero" to cover everything a C/C++ needs to know about C# and .NET. This chapter grew too large to be part of the book, so he spun it off into it's own book. This new book, .NET Book Zero, is available for free. As in beer.
Even if you've been in C#/.NET for a while, it never hurts to review the basics, and there is no better teacher than Petzold.
