I have had a couple of Dick Francis books sitting on the shelf gathering dust, and not being a horse racing fan, have never given it a go. But I am glad I did. Certainly this book was about relationships, frienship, treachery, revenge, and very little to do with racing. Written in the 80's some of the technical side is rather dated, but that's an observation.
Without spoiling any of the story, a physics teacher is given a computer disc with a complicated mathematical formula that has the ability to predict accurately the outcome of races. However some very unpleasant men want the disc, and they are not afraid to be very persuasive. The teachers younger brother is the horse racing fan and this story affect both their lives over a 20 year period.
If you like a good thriller, with a very plausible plot this is a great book