The Practice Effect

Physicist Dennis Nuel was the first human to probe the strange realms called anomaly worlds -- alternate universes where the laws of science were unpredictably changed. But the world Dennis discovered seemed almost like our own -- with one perplexing difference. To his astonishment, he was hailed as a wizard and found himself fighting beside a beautiful woman with strange powers against a mysterious warlord as he struggles to solve the riddle of this baffling world.

David Brin is a scientist and the bestselling author of Sundiver, The Uplift War, Startide Rising, The Practice Effect, The Postman, Heart of the Comet (with Gregory Benford), Earth, Glory Season, Brightness Reef, and Infinity's Shore, as well as the short-story collections The River of Time and Otherness. He has a doctorate in astrophysics and has been a NASA consultant and a physics professor.