This book takes you from sketch to finished painting. The instructions are basic but clear.

It covers basic head proportions (baby's, 3 & 8-year-old, teenager, adult); rendering the eye (and other features) in oils and coloured pencil. Painting hair and beards, etc.
I found the tips on determining the tonal value, very good - squinting your eyes at the subject to determine basic tonal scales was Something I hadn't done since college.
There are also studies of figures in action - great for bulking out crowd scenes.

I discovered a great way to visualise the head in different positions and from different angles. Basically it involves sketching your character's features an up-turned paper cup and then turning it as required. It's not an exact formula, but I think it would work well for basic positioning or even cartooning - when you have invented a character from your head and need a source of reference to develop the look further. This is one thing I have taken from this book that I will be incorporating into my design work in future. ( )