“In one hundred and nine well-packed pages one finds an exposition which is always fresh, proofs which are sophisticated, and a choice of subject matter which is certainly timely. … Most pages exhibit a zest for play as well as work which is refreshing.” – E. R. Lorch (Bull. Amer. Math. Soc.)
It has been several years since I've read this book, but I have occasionally returned to it for reference. It is eminently readable, even for someone lacking basically any subject-area knowledge. However, it suffers for the same reason, in that it does not get to any majorly interesting results. It serves exactly as the title says, and no more.