Only Henry Petroski, author of The Pencil, could make one never pick up a paper clip again without being overcome with feelings of awe and reverence. In his new book the author examines a host of techno-trivia questions - how the fork got its tines, why Scotch tape is called that, how the paper clip evolved, how the Post-it note came to be, how the zipper was named, why aluminum cans have hollow bottoms - and provides us with answers that both astonish and challenge the imagination. In addition to an extended discussion of knives, forks, spoons, and other common devices, the author explains how the interplay of social and technical factors affects the development and use of such things as plastic bags, fast-food packaging, push-button telephones, and other modern conveniences. Throughout the book familiar objects serve to illustrate the general principles behind the evolution of all products of invention and engineering. Petroski shows, by way of these examples as well as a probing look at the patent process, that the single most important driving force behind technological change is the failure of existing devices to live up to their promise. As shortcomings become evident and articulated, new and ''improved'' versions of artifacts come into being through long and involved processes variously known as research and development, invention, and engineering. He further demonstrates how the evolving forms of technology generally are altered by our very use of them, and how they, in turn, alter our social and cultural behavior. In this wonderful mixture of history, biography, and design theory, Henry Petroski brings us to an understanding of an essential question: By what mechanism do theshapes and forms of our made world come to be?