Halpern (Math & Physics/Philadelphia College of Pharmacy and Science) provides a succinct, eye-opening exploration of causality, synchronicity, and time's directionality--with no math! Is time's passage a physical fact or merely an illusion caused by our own biological perception? Is time cyclical and repetitive, progressing linearly upward toward increasing organization, or declining toward ultimate decay? Is time travel possible in both directions? The history of humanity's relationship to time and the means with which We have attempted to comprehend its nature are laid out here along with some very intriguing questions, the answer to nearly all of which remains: Scientists don't know. Just when most experts agreed that the universe was headed inexorably toward heat death and nothingness (and therefore that time was linear, finite, and headed downward), the study of chaos revealed patterns forming out of apparently random beginnings--a possible physical corollary to biological evolution. Neatly instantaneous thought processes lead a number of theorists to suspect that synchronicity, not causality, may be the operating principle behind human intelligence; some researchers believe that a kind of ""biological special relativity"" causes psychological time to pass more quickly for older people than for younger; and many scientists now consider time travel conceivable into the future, but impossible into the past. Halpern's emphasis on the link between individuals' feelings about human mortality and their opinions on the structure of time proves especially enlightening and entertaining, while his conclusion--that the nature of time seems to be unknowable--is convincing. A tasty intellectual treat, despite its dry style.