Take a board with 64 squares on it. Put a grain of wheat on the first square--two on the second--four on the third. Keep doubling in this manner and you will find there isn't enough wheat in the world to fill the sixty-fourth square. It can be the same with compound interest.
After some sudden and unspecified catastrophe has depopulated England, the countryside reverts to nature, and the few survivors to a quasi-medieval way of life. The first part, The Relapse into Barbarism, is the account by some later historian of the fall of civilisation and its consequences, with a loving description of nature reclaiming England. The second part, Wild England, is an adventure set many years later in the wild landscape and society.
Wilbur Murphy sought romance, excitement, and an impossible Horseman of Space. With polite smiles, the planet frustrated him at every turn--until he found them all the hard way!