Farnhams Freehold

Farnham is a self-made man who sees nuclear war coming and who builds a shelter under his house; only to find it thrust into a strange universe when the bomb explodes. In this future world all civilization in the northern hemisphere has long been destroyed, and Farnham and his family are fit to be slaves under the new regime. Heinlein's story is as engrossing now as it was in its original form decades ago.