“On Computable Numbers, with an Application to the Entscheidungsproblem” is a hugely important work, and Petzold's book "The Annotated Turing" makes it very accessible. I highly recommend anyone who is interested pick up a copy. High school education is all that's really needed.

Turing was decades ahead of the rest of us. It's a shame that we're portraying him so inaccurately (though really, not nearly as shameful as how we treated him when he lived).