What Book Shall I get?

Lately I've been wondering what book I should buy. I have narrowed it down to two categories Cryptography, or fractal. Please let me know what you're thinking. I've always been interested in Computer Cryptography and have read a book or two in the past on the subject. However this time around I want something current and fresh. Recently I remembered looking at fractal images in 9th grade, I've always wanted to sit down and create one. And post about it. Considering that there isn't very much attention on the subject.

Let me know what you all think even if it’s not a book on these two categories.