First published in 1976 'The HAB Theory' was accepted as one of the finest Apocalyptic and post-apocalyptic works of fiction. Based on a theory postulated by a real scientist named Hugh Auchincloss Brown it deals with the inevitable possibility that soon the Earths magnetic poles with swop.
The HAB Theory has an immediately disturbing hypothesis: The earth falls over on it's side or ''capsizes'' about every 3,000 - 7,100 years. During a period of about 12 hours, the land that was under the North and South poles moves from the cold point at the earth's axis of spin to a hot point in the tropics.
What the book dwells on is the effect on the planet and its inhabitants when a catastrophic event occurs.
The novel is currently being produced as a movie and is expected to air in about 2010. But if you want a gripping read it is still available, last being reprinted in 2000, and is 500 pages long.
jenray
Pro 
I've been reading about this for years now...there are a whole load of theories out there as to the effects of such a shift...some scientists think that it won't have much effect, others that it will be catastrophic...the last major one was 178,000 years ago I believe and that did have major effects, but there have been regular minor adjustments over the millenia for as long as the earth has existed apparently...big hugs...another thing to worry about...HLOL...