It's a sad fact, but all of the great time-travel novels ever written were destroyed by actual paradoxes, when time travelers went back to meet the authors and accidentally stopped the novels from ever being written. Heinlein's Infinite Loop, Asimov's Foundation and Time, C.S. Lewis's Lord of Time, and even H.G. Wells's The Time Machine — the original, not the pastiche the time traveler wrote from memory.