When I was a kid, I read a great short sci-fi novel that I took out of the Don Mills Public Library in Toronto. I'm pretty sure it was published in 1980 (or perhaps 1979), and it was called "Replay".
I know there's a 1986 book about time travel called "Replay" by Ken Grimwood, and it has a similar story, but it's a different author.
In the Canadian one, a failure of a man in 1990 sees some kind of anomaly, touches it, and goes back to 1980 (when the book came out). He uses his knowledge of the future to get rich by 'inventing' the gadgets of the future, like roads with magnetic disks so cars can drive automatically, flat-panel 3D displays, and hydrogen cells for the self-driving cars. He also uses his knowledge of future marketing and ad campaigns to promote his business. But of course, there are a few catches along the way... Pretty nifty predictions, even though the author was about 40 years early.
I've tried searching on Amazon and eBay, but with no luck. I remember the cover had a drawing of a man's split down the middle, with one side colored red and the other green. Aside from that, no clue.
Thanks in advance!