The concept of time and its similarity to or difference from space has provoked vastly different ideas among philosophers, physicists, and other thinkers. According to F.M. Christensen, previous work on the theory that time is like space (as arguably required by the Theories of Relativity) has failed to reveal fully all its consequences. Christensen's analysis examines evidence for and against that theory, and compares and contrasts other concepts of time. Also discussed are such perennial issues as the asymmetry of time, the relationship between causation and time, and the problem of inertia. The final chapter is devoted to the import of the Theory of Relativity for the nature of time. In addition to linguistic analysis, Christensen draws on concepts from modern physics. His conclusions will be significant for both philosophers and physicists.