I’m a big fan of Charels Petzold. I caught his pre-conferrence session on WPF at PDC back in 2009 and I really enjoyed it. Also he has an uncanny resemblence to Terry Pratchett.
Pratchett and Petzold (but which one is which? – and no cheating by looking at the T-Shirt)
For those who don’t know Petzold wrote the defacto standard on programming the win32 API – Programming Windows. He also wrote one of the first useful WPF programming books – Application = Code + Markup.
Anyway he has set about writing a book for programming Window Phone 7 Series and more interestingly he is giving it away for free. I for one can’t wait.