The basic idea put forward in the book is that you begin with an abstract mark and then add another where you instinctively feel it should go and then another and so on and on until you feel you want to stop and the piece is complete and satisfying.
I have done several of the exercises shown in this book and found them to be very interesting. If nothing else, completing them has had me thinking hard about balance and line and quality of mark in my work.
In line with much that I seem to be doing at the moment, many of the exercises are to be completed in black (paint, pencil or charcoal) on white paper. I have some leisure time coming up and plan to try a few more.