It is a great book, and this illustration is an ideal example of some of the points made in the Drawing for the Artistically Undiscovered book by Blake and Cassidy.
For those of you who are also sketching, trying to find your style, or who just love drawing, I am going to share some passages from this book:
Don't agonize over your work, and don't dash through it either. Neither extreme has any special virtue.
Overworking is against the rules. If you grip the pen tightly, bear down hard, push your nose into the paper and agonize over every line . . . your drawings will look like hard labor. If you back off, relax, do a little sketching and stop before you need to, your drawings will begin to look like sparks of spontaneity and fun.
(Try) to capture the spirit of something . . . sneak into the heart of your subject by going direct. We're not so much interested in the appearance of something, so much as the 'something' itself.
Think of it this way: An effective poem wastes no words on its way to the core of its subject. A successful drawing wastes no lines on the same trip. One can spend weeks on marvelous painting of a rabbit, accurate to the tiniest detail -- and yet still miss its essential rabbit-ness. And then dash off a funny little sketch in a few lines -- and pin that bunny's soul to the paper.
We could apply that advice to life too I think.