An imaginative look at airplanes through such questions as "What if airplanes didn't have air?" and "What if airplanes could go into space?"

An imaginative look at space with such questions as "What if the sun went out?" and "What if there were Martians?"

Historians and inquisitive laymen alike love to ponder the dramatic what-ifs of history. In these never-before-published essays, some of the keenest minds of our time ask the big, tantalizing questions: Where might we be if history had not unfolded the way it did? Why, how, and when was our fortune made real? The answers are surprising, sometimes frightening, and always entertaining. This provocative collection of essays features today's foremost...

Discusses what might happen if an asteroid hit the Earth.

Explores reasons why humans might want to live in space, as well as technical problems and scientific considerations involved in establishing a space colony.

A discussion of major infectious diseases, how they are spread and treated. Outlines means by which governments and health organizations can handle these diseases and prevent epidemics and pandemics.

Rain forests under threat -- African wildlife -- Oceans -- Asia's animals -- North American wildlife -- Antarctica.