Thomas then disappears, and Sierra learns that he was lost in a boating accident on the Aegean Sea even though he was supposedly going for surgery to a hospital in Delaware. She soon comes upon a photograph, dated 1883, of Thomas O'Leary looking exactly as he does in her time of 2042. Sierra, along with her boyfriend Max, another classical scholar, is determined to find out the truth about both the old manuscript and her mentor Thomas. Her quest takes her to London, ancient Rome at the height of its empire, the New York of the late 19th century, the Athens of Socrates, the fabled library of Alexandria and the not-too-distant future.

Along the way, she is threatened by a number of dangers, among them murderous Roman soldiers, and meets several historical figures, including a young Plato, the noted 19th-century American publisher William Henry Appleton, the charming and amorous Alcibiades (a favorite of Socrates) and an enigmatic inventor of classical times, Heron of Alexandria. Will a successful attempt to rescue Socrates leave history undisturbed, or instead tie it up in impossible paradoxical knots?

A lively and intricately plotted adventure

Midway through the twisting currents of The Plot to Save Socrates, Heron the inventor offers his theory of time, derived from the pre-Socratic philosopher Heraclitus: "Heraclitus recognized that you can never step into the same river, exactly the same river, twice, because new water is always flowing. And yet we are right in thinking there is a reality to the river. ... So the river always changes, yet stays the same, has continuity—both are true." What is true of the river is also true of time, and the fact that Heron, Sierra and others can move as they do through time in chairs designed for that purpose seems to demonstrate the validity of that observation.

The problem is that Sierra, Max, Thomas and others aren't sure at the outset whether they should be trying to save Socrates or preventing his rescue. Complications ensue when Sierra realizes that, whatever happens, the key to answering her questions is discovering the truth about the unknown Socratic dialogue her mentor has shown her. She also can't know whether she is destined to return to her own time or, after several close calls, will have to die herself in order to resolve any paradoxes.

Paul Levinson brings both intellectual heft and affection for his delightfully depicted characters to this highly original story of time travel. His settings, which range from mid-21st-century New York City, London and Athens to their earlier counterparts, are conscientiously researched and well rendered; if some readers might wish that he had lingered in them longer, with a bit more detail and more attention to the fascinating people who populate this novel, others will appreciate his lucid and economical style and the fast pace of his tale. Levinson maintains control of his tangled plot while bringing all of its threads together in an ending that is emotionally satisfying and extremely moving. The Plot to Save Socrates will provoke thought long after readers have finished the book, at which point many may want to pick it up and read it again, to savor its twists and turns.