Brief biographies of four gifted American technologists. In each case, Mitchell focuses on a particular achievement, leading up to it with incidents from earlier life. Ford is pictured trying to perfect the Model T in a series of races; his farming origins and introduction of the assembly line are mentioned, and the book ends abruptly at a mid-life picnic. Eastman's impoverished early life is given in choppy detail; the development of an easily used, portable camera and film reads more smoothly; Eastman's character, idiosyncratic but benevolent, emerges by the book's end. Least familiar is Matzeliger, half Dutch and half black, native of Dutch Guiana. An inveterate tinkerer with machines, he made his way in spite of prejudice to the factories of Lynn, Massachusetts, where he finally got financial backing for his revolutionary invention, the shoe last. Carver and the peanut is a familiar enough story; Mitchell emphasizes his lifelong struggle against humiliations offered by a white world and declined by this charismatic humanitarian. These are adequate, somewhat fictionalized, accounts. Except for Shoes, they lack explanatory material on sources or what is known or conjectured about the subject; the stories are well-known, of course, but not to young readers, who need to learn that sources are important. Mitchell essays a perky, colloquial style which is more awkward than entertaining. Black-and-white full-page drawings enliven the texts; especially in the Eastman (stylishly well composed) and Ford (careful details on early cars, although more would have been welcome). These should be useful--there's always heavy demand for easy biographies.