Thin blue ride

There have been various calls over the last few months for cyclists to engage in some sort of formal training before taking to the road.
Notwithstanding the logistical challenge of making everyone who owns a bike doing some sort of test and enforcing it, it seems to me to be unnecessary.
Quite apart from anything else, most people I know who cycle, take a keen interest in their riding style.
The best thing I ever did for my cycling and car driving for that matter, was learn to ride a motorbike.
The thing with riding a motorbike is that if you crash, you're basically toast meaning you have to know what you're doing.  I'm by no means the best bike handler in the world but I'm much, much better than I used to be.
Simple things like checking blind spots - something which car only drivers seldom do - are given extra importance on a motorbike as they become 'your lifesaver'.
Many cyclists and motorcyclists like to think of themselves as students of the road and if I could recommend one book to read, it'd be the Police motorcyclist's riding guide: Roadcraft.

Warning: may include doughnuts

If you want to know how to read a bend, all about lane positioning and being safe at speed, this is a great place to start.
My copy is from the early 1980s and it basically explains defensive riding techniques before the term was invented.
You can pick copies up for a couple of quid and it'll make you a better rider.