I would like to second - "How Innovation Works" by Matt Ridley is an excellent book. I see the kindle version is £1.99 on amazon.co.uk atm - what a bargain. Most innovations we all enjoy and cherish are a product of long chain of trial and error by different people at different times. Often the theory is understood poorly (if at all) at the time of the invention, and developed after. Luck plays a role in particular person X inventing Y at time Z. But given the number of other people (not-X) that come up with similar invention ~Y at similar time ~Z, looks like Y would have been invented by someone at about time Z.