Great Tutorials
Yim's book provides a wealth of information for intermediate and more experienced artists familiar with head drawing. I have been doing portraits for three years, and Yim's book provides a unique philosophy and approach to portrait drawing that supplements an academic study. His portraits have an amazing sensitivity and respect for the model and convey a certain mood.
Beginner students might want a book that breaks down each feature into a series of steps. For them I suggest Vanderpoel's Human Figure, Andrew Loomis', or George Bridgman's books. Yim's doesn't break down each feature. He is writing for artists at an intermediate and advanced level.
