Past, Future And Paradoxes

Time travellers can explore the past, the future, causality paradoxes or all three. HG Wells' Time Traveller discusses the past and hints at paradoxes but focuses on "futurity" to such an extent that his narrative presents a miniature future history of mankind and of life on Earth. His literary successors in Poul Anderson's Time Patrol refer to the future but focus on the past, historical and prehistorical, and on both paradoxes, completing causal circles in order to prevent causality violations. Their streamlined, mass-produced timecycles are like updates of the Time Traveller's experimental nineteenth century contraption. Human devolution or self-destruction is prevented by the intervention of our evolutionary successors. The Time Machine and the Time Patrol are literary opposites: a single slim volume as against an increasingly intricate series eventually collected in two long volumes.

Past, future and circular causality, although not also causality violation, are combined in Anderson's The Corridors Of Time and There Will Be Time and the latter also incorporates his Maurai future history. Amazing. Heinlein, Asimov and Anderson all connect time travel with a future history series but only Anderson does it right.