Paul J. Nahin 
Time Travel 

From H.G. Wells to Isaac Asimov to Ursula K. Le Guin, time travel has long been a favorite topic and plot device in tales of science fiction and fantasy. But as any true SF fan knows, astounding stories about traversing alternate universes and swimming the tides of time demand plausible science. That’s just what Paul J. Nahin’s guide provides.An engineer, physicist, and published science fiction writer, Nahin is uniquely qualified to explain the ins and outs of how to spin such complex theories as worm holes, singularity, and relativity into scientifically sound fiction. First published in 1997, this fast-paced book discusses the common and not-so-common time-travel devices science fiction writers have used over the years, assesses which would theoretically work and which would not, and provides scientific insight inventive authors can use to find their own way forward or backward in time. From hyperspace and faster-than-light travel to causal loops and the uncertainty principle and beyond, Nahin’s equation-free romp across time will help writers send their characters to the past or future in an entertaining, logical, and scientific way.If you ever wanted to set up the latest and greatest grandfather paradox-or just wanted to know if the time-bending events in the latest pulp you read could ever happen-then this book is for you.