Ever since humans first stood on two feet, we've hoped to explain how everything in the universe fits together. It is one of our most basic intellectual desires. Over the course of history, Theories of Everything have ranged from mythologies and legends that evoke sprites and nymphs, to worldwide religions, to science. The scientific approach to the Theory of Everything is perhaps the most compelling because in science, challenges to what we think we already know are a vital part of the theory-refining process. Science is unstable, perpetually evolving, always trying and never quite succeeding to address, well, Everything. In science, Everything is always just out of reach.

In Universe on a T-Shirt, Dan Falk traces the evolution of the Theory of Everything from ancient Greece to the most recent hat in the ring, String Theory. The common thread woven through this tapestry of scientific achievement is the people who were not only doing the basic science, but also thinking about how their findings fit into the bigger picture. As Falk puts it, "this book is a history of ideas, but it is also a story about people."

It is also a story of the very small and the very big. Since Einstein published his General Theory of Relativity, the search for a Theory of Everything has focused on the unification of gravitation and quantum mechanics. Einstein himself spent the last years of his life working hard to unite the two, with no success. String Theory is thus tremendously exciting in that it may provide something not even Einstein could create: a plausible tie between gravitation and quantum theory.

But if you are looking for a comprehensive description of String Theory, you will not find it here. Falk presents String Theory using the same broad, transparent language he uses to describe all the other theories in the book. Universe on a T-Shirt is not intended for those interested in minutiae--rather, it is a concise, effective primer and a valuable reference for those with a general interest in the Theory of Everything, but who aren't actually physicists. It's not everything you'd ever want to know about Everything, but it's enough. AARON BEAM