I've posted a complete draft of my flânerie A Functional Introduction to Computer Science (Part II). Part I has been available for a couple of months. Like my other flâneries, it's based on courses I developed at the University of Waterloo, but is self-contained and freely available under a CC-by-SA 3.0 licence. Part I uses the Racket teaching languages, but Part II (which focusses on effects, including mutation) uses full Racket. This completes FICS, but I intend it to be a living document, so if you have any comments or suggestions, I'd be happy to hear from you!