Currently, Blog Central is reading for the first time SM Stirling's Nantucket Trilogy, Volume II, Against TheTide Of Years. Not only fascinating in its own right, this work has sparked comparisons with:
Poul Anderson's History of Technic Civiliztion;
Anderson's Time Patrol series;
his "Flight to Forever";
his The Corridors Of Time;
his There Will Be Time;
his The Star Fox;
Poul and Karen Anderson's The King Of Ys; Doctor Who;
HG Wells' The Time Machine;
Audrey Niffeneger's The Time Traveler's Wife;
James Blish's After Such Knowledge.
That is quite a lot and, as usual when I compile such a list, more than I had expected.