Ebook: Principles of quantum mechanics

The book begins with a very nice inroduction on the math you'r going to need, the Dirac notation (with a fine review to matrix and vector calculus using Dirac's notation), then he applies this math to a classical problem: two masses coupled with springs.After this introduction there's a good begining (about the first half of the book) on the basics of quantum mechanics, but the second half I didn't like as much (I looked for another book: Cohen's), although it is still fine.