May the devil walk behind ye! Book

Hasn't remained overly relevant given its focus on Miranda, but I Still found value in reading it in 2018. More value in the early parts which where generic rather than Miranda based.

I did make a few notes because some of the early sections still resonated:

page 7 "...specifications can have mistakes in them, and this will manifest itself in unexpected and unwanted features in a formally correct program. Hence correctness is only an approximation to quality"
page 25 - "The purpose of precedence rules is to resolve possible ambiguity and to allow us to use fewer parentheses in expressions."
page 37 - "The code can only tell you what the computer does, not what the result was meant to be."

Also a reminder of the importance of concepts such as: Equivalence, Preconditions, Postconditions - and you'll get that in any book on formal methods.