Following a recent thread on ILUG, I was reminded of what I consider an invaluable resource for LaTeX: The Not So Short Introduction to LaTeX (or LaTeX in 139 minutes – you’ll have to read it to discover why 139).
This document held a place of esteem on my desk during my research years in UCD and I am very grateful to its author, Tobias Oetiker. I think I still have a coffee stained version somewhere in the house…