The Practice Effect
David Brin1984

From one of the most critically acclaimed and well-loved authors of contemporary science fiction, a highly imaginative and exciting story as only David Brin can write... Physicist Dennis Nuel was the first human to probe the strange realms called anomaly worldsalternate universes where the laws of science were unpredictably changed. But the world Dennis discovered seemed almost like our ownwith 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 struggled to solve the riddle of this baffling world.

Titre original : The Practice Effect (1984)