THE traditional face of survivalism is that of a shaggy loner in camouflage, holed up in a cabin in the wilderness and surrounded by cases of canned goods and ammunition.

It is not that of Barton M. Biggs, the former chief global strategist at Morgan Stanley. Yet in Mr. Biggs’s new book, “Wealth, War and Wisdom,” he says people should “assume the possibility of a breakdown of the civilized infrastructure.”

“Your safe haven must be self-sufficient and capable of growing some kind of food,” Mr. Biggs writes. “It should be well-stocked with seed, fertilizer, canned food, wine, medicine, clothes, etc. Think Swiss Family Robinson. Even in America and Europe there could be moments of riot and rebellion when law and order temporarily completely breaks down.”

Survivalism, it seems, is not just for survivalists anymore.

Faced with a confluence of diverse threats  a tanking economy, a housing crisis, looming environmental disasters, and a sharp spike in oil prices  people who do not consider themselves extremists are starting to discuss doomsday measures once associated with the social fringes.