Time travel in the pulps -- Special relativity and time travel in the future -- Time travel to the past -- Hyperspace -- Time as the fourth dimension -- The block universe -- When general relativity made time travel honest -- Paradoxes: changing the past, causal loops, and sex -- Time machines that physicists have already 'invented' -- Faster-than-light (FTL) into the past -- Quantum gravity, splitting universes, and time machines -- Reading the physics literature for story ideas.