Reading a book cover-to-cover is, for me, a bad way to learn a language. I usually pick things up very quickly when I try to implement things using them that I am both familiar with and faced with annoying issues stemming to the language they are currently implemented in. If you don't have one of those, think about something you hate, and fix it with this.

If the book is good documentation, then use it. But you may benefit from focusing more on problems than completing a book.