I just loved The Technicolor Time Machine, by Harry Harrison.
There is another time travel book by Harrison called A Rebel in Time (My favourite Author, along with Michael Stackpole, by the way).
I can recommend both books, Harrison’s time travel stories were really well thought out and great to read.
Quoth The Gaspode:
Yes, you can (Number of the Beast, anyone? Or The Cat who Walks through Walls?), but when you go right with him, you’ll go very right, indeed. I’ll enthusiastically second the three you mention there (The Door into Summer, By His Own Bootstraps, and All You Zombies), and also add Time Enough for Love.
By contrast, I prefer to consider that Asimov never wrote any time-travel stories, as I find that much more palatable than saying that The End of Eternity is about time travel. It’s just a cliched space opera with a very clumsy find-and-replace overlaid on it. “The Ugly Little Boy” is good, but for reasons unrelated to time travel, and “The Red Queen’s Race” is also OK, but other than that, it’s definitely not his proper sub-genre.
For a time-travel book with a difference, see if you can find
A Dream of Wessex - Christopher Priest
TTFN
JP
Ok, it’sn’t bout time travel, but it’s an organization moving through time seeking history failures, trying minimum changes to obtain maximun results, isn’t it?
Ok, not travelling in time with a machine but still the result is interesting, not neccessarily to be liked by everyone.
Bring the Jubilee by Ward Moore. Alternative history with some time-travel elements. Good story, with some philosophical ruminations tossed in here and there.
Terraplane and Elvissey by Jack Womack are both very good.