50 Physics Ideas You Really Need To Know by Joanne Baker. ISBN 978-1-84724-148-1. This book, like the other "50 Ideas" books, contains 50 short descriptions of physics related subjects. Each subject gets four pages. This also includes diagrams and boxes on special terms (for example, in the section on chaos theory there is a box on the "butterfly effect".) Other subjects include Mach's Principle, Newton's laws, Nuclear fission, Nuclear fusion, the Big Bang, etc. These descriptions are very high level and aimed at a general audience. There are no references to help pursue a subject further, however, one can easily look them up in Wikipedia. I got his book for $5.99 at Borders.