The united 'Second Empire of Man' spans vast distances, due to the Alderson Drive which has enabled humans to travel easily between the stars. After an alien probe is discovered, the Navy dispatches two ships to determine whether the aliens pose a threat… Called by Robert A. Heinlein: "Possibly the greatest science fiction novel ever written," this magnificent exploration of first contact and a truly alien society is a "must read" for science fiction fans."As science fiction, one of the most important novels ever published."- San Francisco Chronicle"Possibly the greatest science fiction novel I have ever read."- Robert A. Heinlein"A superlatively fine novel…no writer has ever come up with a more appealing, intriguing, and workable concept of aliens."- Columbus Dispatch"A spellbinder, a swashbuckler…And, best of all, it has a brilliant new approach to that fascinating problem -- first contact with aliens."- Frank Herbert"One of the most engrossing tales I've read in year…fascinating."- Theodore Sturgeon"Intriguing and suspenseful…the scenes in which the humans and aliens examine one another are unforgettable."- Minneapolis Tribune“Nobody does it better than Niven and Pournelle”- Tom Clancy “The team of Jerry Pournelle and Larry Niven is one of the best in science fiction.” - The Washington Times “Few writers have a better pedigree”- Los Angeles Times