Book excerpt: Chief engineer Thomas J. Kelly gives a firsthand account of designing, building, testing, and flying the Apollo lunar module. It was, he writes, “an aerospace engineer’s dream job of the century.” Kelly’s account begins with the imaginative process of sketching solutions to a host of technical challenges with an emphasis on safety, reliability, and maintainability. He catalogs numerous test failures, including propulsion-system leaks, ascent-engine instability, stress corrosion of the aluminum alloy parts, and battery problems, as well as their fixes under the ever-present constraints of budget and schedule. He also recaptures the exhilaration of hearing Apollo 11’s Neil Armstrong report that “The Eagle has landed,” and the pride of having inadvertently provided a vital “lifeboat” for the crew of the disabled Apollo 13.