Finished Jack of Eagles
by James Blish, which was very interesting, about a guy who develops the ability to see the future which wrecks his life and then things get strange lol, including alternate universes. It would actually make an interesting TV/movie plot, though the climax is a little esoteric for anyone except maybe Terry Gilliam to wrestle with.
And as I began to suspect, it had absolutely nothing
to do with that lovely orange Chris Foss cover I posted above!
Gotta love the 70s publishing industry.
Based on recommendations above and what I read about it, now on to lots more alternate realities in The Coming of the Quantum Cats
by Frederick Pohl.