I generally agree with James Ladyman's highly favorable review on the back cover of the book. This book is among the best introductions to the philosophy of science that I've run across so far.
French has a pleasantly informal and chatty writing style and starts the book fairly gently in the earlier chapters, so this book should be quite accessible for the motivated general reader; that's no small accomplishment for a subject as tough as philosophy of science. And the last few chapters venture into more sophisticated material, so the book can also benefit readers who already have some background in the subject.
An added plus is that French draws examples from many branches of science, and he explains these examples clearly, so the book provides some education in science itself as a fringe benefit.
Overall, I can highly recommend the book to anyone interested in philosophy of science, ranging from beginners seeking an introduction to old hats seeking a review. Some prior background in philosophy and/or science would be a definite plus, but isn't absolutely mandatory.