Einstein's Riddle features fifty of the toughest logic problems, lateral-thinking puzzles, and tests of mental agility. The puzzles challenge our preconceptions, tell us about how we reason, and provide a rigorous intellectual workout.

Riddles, paradoxes, and conundrums have been confusing and confounding people since at least the time of the Ancient Greeks. The eponymous riddle, according to legend, was devised by Albert Einstein as a child. He claimed that only about 2% of the population would be able to work out the correct answer. There are no tricks and there is only one answer. It requires the cool application of logic to solve – and a lot of patience.