When astronomers notice that a newly discovered object in the solar system seems able to accelerate and decelerate, they realize that it must be a powered vehicle, heading directly toward Earth. Ominously, the ship appears to have jettisoned its power source, a Bussard ramjet, in a move that recalls Cortez burning his ships before facing the Aztec empire. The Soviet and American governments, though intensely suspicious of each other, mount a joint mission to greet the aliens, but the invaders promptly attack the welcoming craft and then turn their laser weapons on dams and highways all over the globe. A landing party of the creatures, called snouts because of their resemblance to elephants, sets down in Kansas and begins taking prisoners. When the president retaliates by nuking Kansas, killing citizens and snouts alike, the aliens respond by propelling an asteroid into the Indian Ocean, devastating a large section of the planet. They demand unconditional surrender or the Earth will be destroyed.

As the authors incessantly remind us, years of narrow-minded opposition to the space program have left the United States in a vulnerable position. A secret project, however, is under way--masterminded by a team of commandos, scientists, and science-fiction writers--to construct a nuclear-powered rocket capable of firing a huge battleship into space, in one glorious kamikaze strike.

FOOTFALL is old-fashioned science fiction in the best sense, combining hard science and technology, warfare and romance. At times, the characterization is thin, and the soapbox philosophy--equal parts Immanuel Velikovsky and Rambo--annoying and intrusive. Even so, the novel is a worthy successor to the Larry Niven and Jerry Pournelle blockbusters LUCIFER’S HAMMER and A MOTE IN GOD’S EYE.