Analytic and elementary number theory Book

I read this book because a professor of mine, who was retiring, gave me this book because I had displayed an interest in the material. That professor was really good. I became a math major as a direct result of that action.

I learned about the elementary theory of congruences from this book. But it is referenced everywhere. I plan to read through more topics in this book later.

I have heard that it has an awesome discussion of the theory of continued fractions.