Understanding Computation: From Simple Machines to Impossible Programs by Tom Stuart https://www.amazon.co.uk/Understanding-Computation-Machines-Impossible-Pro

Understanding Computation: From Simple Machines to Impossible Programs by Tom Stuart https://www.amazon.co.uk/Understanding-Computation-Machines-Impossible-Programs/dp/1449329276/ https://www.amazon.co.uk/Understanding-Computation-Machines-... Not finished it yet, but it's a joy to read and explains fundamental concepts of things like parsers, interpreters and Lambda Calculus using minimal Ruby syntax.