In no way do I mean the following comments to detract from what may be a marvelous book.  But as a professional artist and long-time teacher and mentor of students, I have found the sight-size method to be a dubious help to many people.  I have had in my figure painting and drawing classes several former students from various ateliers in the Midwest and East, and they have all used this method in my classes.  Because they made such glowing claims for it, several other students were motivated to try it.  Fine, for their artistic future is their own.  They are not my possessions, merely people in my classes seeking to draw or paint better, and I am happy for them to use anything (except opaque projectors!) that works for them.  But I have witnessed a lot of sight-size activity, and here are my primary concerns.

First, the sheer limitations of the sight-size method.  I do not want to be limited either by the size or perspective of or in what I draw.  If I learn to draw accurately WITHOUT sight-size, I can draw a figure (or anything else) any size I want successfully: life-sized or tiny images for the artistic trading cards (ACEOs) so popular today...or anything in between.  Also, I can stand close to the model or far away to achieve the proper perspective (Try looking at the feet of a standing model when you are two feet away and see how much they change when you back up ten yards.) for my purpose.  

If I am using sight-size, I am severely restricted in where I can stand and how large I can work.  Of course, I can scale up a smaller drawing made using sight-size, but why learn such a limited method in the first place as my PRIMARY drawing method?  Of course if you want to learn an ADDITIONAL method for specific circumstances, that is fine.  But why learn one that is so inherently limiting as your principal method for drawing.  Why not just learn more basic things (comparative measurements, anatomy, etc.) and draw so much that you learn to draw well as second nature?  Or rather first nature?

Second, an intangible: the sheer rush of picking up a pencil or other tool and drawing well...naturally, almost as a bird flies...what we sometimes call effortlessly.  The whole sight-size method is such a mechanical process that for many people, it robs the joy of drawing by its mechanistic procedures.  I am not against some kind of measuring while drawing; I still do that after decades of drawing...when I need to.  But learning the sight-size method becomes a true inhibiting crutch for many people, and it robs them of much of the fun in what ought to be a joyful activity.  Remember that this method is advocated primarily by the same people who insist their students spend months or years with plaster casts in black and white or other  two-toned media before moving to living beings in color.  That is obviously fine for some students, for these ateliers have produced some brilliant artists.  But like most learning methods, it is certainly not the best approach for everyone.  A quick perusal of modern learning methods in ANY subject will disprove the claim that there is one best method for EVERYONE to learn something.  It is the job of the true teacher to help find a method for each student, not to try to force the student into a particular method the teacher prefers.

Any artist who has learned to draw using techniques (even measuring ones) other than sight-size can draw tiny or huge with enough practice from virtually anyplace he or she can see the subject being drawn.  That is true freedom.  Sight-size may eventually lead to a general ability to draw with more fluency, but it is often a long,  frustrating, and severely restrictive path.  I do not recommend it as a method for most artists.