Why has no one come up with a time machine? Time travel has long excited man's imagination. And, while it has been a long standing fantasy, it has long been a nagging thorn in the side of theoretical physics. The problem is that the microscopic constituents of matter behave symmetrically in time. For every trajectory of a collection of elementary particles that moves on a one-way into the future, there is a corresponding trajectory that moves in precisely the opposite fashion into the past; each trajectory is equally viable. Furthermore, there is a one-to-one correspondence.

So why do we see only events that move into the future, things that have never happened before, systems with ever increasing disorder? This is the time-asymmetry paradox. The author "will resolve this paradox in a simple, straightforward fashion. Fundamentally, it is a matter of counting."

But there is more, a bonus: This book is also something of a science memoir. Besides dealing with this paradox in time, the author takes a Joycean romp through such diverse topics as: humor as an adaptive trait, the conflict between determinism and free will, the ear as an impedance-matching device, the biology of happiness, the rainbow paradox, why we get energy from taking atoms apart (fission) and putting them together (fusion), why flags flap, and why dogs wag their tails.

There is time for whimsy and exploration in A Paradox in Time.