Have you ever wondered how stealth planes achieve invisibility, how sunken ships are found, or how fishermen track schools of fish in vast expanses of ocean? Radar and sonar echolocationa simple matter of sending, receiving, and processing signals. Weaving history with simple science, Mark Denny deftly reveals the world of radar and sonar to the curious reader, technology buff, and expert alike.He begins with an early history of the Chain Home radar system used during World War II and then provides accessible and engaging explanations of the physics that make signal processing possible. Basic diagrams and formulas show how electromagnetic and sound waves are transmitted, received, and converted into images, allowing you to literally see in the dark.A section on bioacoustic echolocation, with a focus on the superior sonar systems of bats and whales and a discussion of the advanced technology of next-generation airborne signal processors, opens the imagination to fascinating possibilities for the future.denny's book gets a two thumbs up from me. It is a clear, beautifully written work on a topic of great interestand one of great mystery. Best of all, it is not a popular science' trivialization of the subject. It is decidedly unusual in that while a bright high school math or science student can read the majority of the book with profit, even graduate engineers will learn from it as well. I certainly did.Paul J. Nahin, author of Oliver Heaviside and The Science of Radio
