1. 入门的，《The Little Book of Semaphores》
The Little Book of Semaphores is a free textbook that introduces the principles of synchronization for concurrent programming.
The approach of this book is to identify patterns that are useful for a variety of synchronization problems and then show how they can be assembled into solutions. After each problem, the book offers a hint before showing a solution, giving students a better chance of discovering solutions on their own.
The book covers the classical problems, including “Readers-writers,” “Producer-consumer”, and “Dining Philosophers.” In addition, it collects a number of not-so-classical problems, some written by the author and some by other teachers and textbook writers.
2. RCU 的作者，大牛 Paul E. McKenney 写的书，《Is Parallel Programming Hard, And, If So, What Can You Do About It?》。这个比较猛，我还没时间看。它也是免费的，英文版可以在这里下载：
我在南京和布拉格的时候见过 Paul E. McKenney，他是一个非常和蔼、热心的人，没有一点儿牛人的架子。:-)