One of my best friends has assembled a rather amazing library of some 200 books: quote books, trivia books, fact books, you name it. The most interesting facet of his collection is the place where it resides--in his bathroom!!! Furthermore, David Feldman's wonderful series of Imponderables books has a place of honor in his library--right next to the toilet paper! (Needless to say, he is a bachelor as of this writing!) When Do Fish Sleep? is Feldman's third book in the series, and one of the best, in that more time is spent pondering questions that people really do care about, such as: "Why do gas gauges take an eternity to go from registering full to half full, and then drop to empty in the speed of light?" (I think we've all been there!) Feldman receives most of his imponderables from readers of the previous volumes, seeks out experts in the relevent fields to answer them (In the above example, that person is Anthony H Siegel of Ametek's US Gauge Division), and prints their response. If no one expert knows the definitive answer, Feldman will print the most prevalent theories instead. There are also many charming and funny illustrations to keep the material from getting too dry. There is also a section in the back called Frustables, which deals with Imponderables that are not easily solved, and their corresponding theories. Finally, the most important feature of this and any other Imponderables book: The articles are just the right length to read when seated "upon the throne." (Well, most of them are, anyway!) So, get When Do Fish Sleep and other Imponderables books right away. Feldman's ready wit will keep you entertained and keep you from having to make that sometimes painful search for reading matter the next time nature calls!