Lambda the Ultimate

Since pi calculus is a hot topic lately, Pierce's Foundational Calculi for Programming Languages might be of interest as an introduction. It very briefly introduces and justifies foundational calculi in general, spends about 10 pages on lambda calculus, then builds on that with another 7 pages on pi calculus.

This quote:

overall flexibilty increases by having fewer components but greater composability.

made me think of HOFs.

A couple more teaser quotes:

A complex system that works is invariably found to have evolved from a simple system that worked. A complex system designed from scratch never works and cannot be patched up to make it work.

...

It's better to be simple than to handle every possible case.