A short treatise on the U-boat presents a lot of information in compact form and deftly leads into its subject by beginning with its most spectacular aspect- diving. After we learn about such things as the ballast tanks and how they increase or decrease the amounts of weight necessary for submerging or rising, our interest is definitely roused. From here on in, submarine history, modern submarine life and duties, the special qualifications for the atomic submarine, etc., etc., become increasingly fascinating to learn about. And Captain Icenhower's knowledge stems from a Navy career and first hand experience.