And so I came across Chris James' The Complete Serger Handbook. It's got a lot of colour pictures to illustrate the text, and sections on needles, thread, tension, stitches, techniques, etc. I especially liked the subsection on elastics and rolled hem (didn't know you could do that!). Most of the information was great for a not quite beginner. A few times the text was outside my experience level, so it's probably a good guide for beginners to intermediates.