This diverting hodgepodge of information may remind readers with long memories of the old, random Book of Knowledge. And these are mostly questions that spring, in everyone, from a childlike curiosity. ""How do they get the stripes into Stripe toothpaste?"" ""How can they tell what a dinosaur looked like from a single bone?"" ""How do they decide who is pictured on US paper currency?"" (The answer to the first may surprise you-the toothpaste isn't striped inside the tube.) Many of the queries are old-hat (on salmon migration, sawing a woman in half, preserving a mummy, etc.); some--on notating choreography, detaching a fresco from a wall--refer to nothing more extraordinary than specialized skills. And a question like ""How do they pick Nobel Prize winners?"" is over its head here altogether. But the explanations vary in length--from a paragraph to a few pages; they are careful to indicate the limits of knowledge (how a firefly flashes is known--but not, still, why); they are clear yet not cut-and-dried, informal yet not cutesy. For fact-fanciers, then, 150 variegated, easy-to-take capsules.