The fame of Asimov's Foundation and Robot series has tended to steal the limelight from some of his other masterpieces, chief among them, The End of Eternity, a book that is hard to find. In this book, Asimov consciously set out to explore the limits of the classic paradox of time travel that has bedeviled so many works of science fiction. As a result, this is a "bare bones" novel; no robots or empires or any other such distractions. Its strength lies in imagination. Asimov looks at our world as it has evolved, and then introduces the organization called Eternity, whose mission is to protect humanity from its own mistakes, by making deft changes in key events over time (past and future). Along the way, he has fun making digs at the unchanging fundamentals of human nature (competition, drive, love) amid centuries of changing social mores. At the heart of the book is the love story of Andrew Harlan and Noyes Lambent, but this tale is just a framework for Asimov to build on. In the final analysis, Asimov is making the point that just as a child learns to walk by repeated falls, humanity's ultimate characteristic is the Schumpeterian desire and ability to innovate through risks. If we are protected from ever making mistakes, we may avoid tragedies, but the human race itself will vegetate and die. As with many of his earlier works, the dialog can be jarring and characters often one-dimensional. For all that however, The End of Eternity ranks among Asimov's finest in the field of science fiction and makes it all the more strange why this book is so difficult to find. Do take the time to lay your hands on it; you will not be disappointed.