Although very occasionally verging on the cooler-than-thou, this book is a pretty damn thorough description of most thing that make people go squelch.
Mainly, although not exclusively directed at heterosexuals, it's a page-turner of another sort - or at least was for me, as I wanted to see what they'd left out.
The answer to that is not a lot. Most every ordinary position, quite a few extraordinary ones, and a lot of well written stuff that sounds like it was penned by people who not only have had but actively enjoy sex, rather than dry medicinal prose.
The illustrations are a laugh too, a million miles away from the ghastly beardy man of the 'Joy of Sex' and its many imitators.
All-in-all, probably one of the best sex manuals on the market, and don't think that sex manuals are just for 'beginners'. You may not learn much new, but if you enjoy sex, and like talking about and discussing sex, you'll probably like this book, especially if you can share it with that certain special someone.