Quid Publishing

Covers the history of mathematics with some of its brightest stars. Mostly covers history but also goes into simple mathematical operations with combinatorics, permutations, binomial theorem and other things. It's pretty simple, but it's good if you want a basic introduction to some math.

It's really short, but sometimes that is a good thing. I bought it because I thought it could give me a better grounding in some math. It was less than 10 dollars.