Sharp, explicit diagrams, by the author, and outline texts packed with information show the development of planes and ships respectively, from their earliest beginnings to recent advancements. Neither book is narrow. Each broadens to show the effect of progress in other fields and each gives a pretty clear idea of the mechanical essentials and concurrent problems involved- especially in flight where they are more difficult. For any of the nautically minded (aero, astro or plain old) in the age group and interested 8 -- 11's as well.