Maybe 3-1/2 stars. (Idea & Layout= 5 stars. Drawing quality= 2 stars.)
Bridgman's The Human Machine is *exceedingly* ambitious in its scope, and could have been exceedingly successful to match, were it not for its *one* pretty obviously glaring problem: these drawings are exceedingly sketchy!
Originally published in 1939, Bridgman passed away in 1943. He was approximately 75 when he made this- possibly a factor in the lack of clarity throughout. If only he had made this at the height of his career(!)- This book is a perfect example of 'what could have been'.
Many people revere this work in spite of all this. It may not compare at 1st glance with the slick, computer-aided & enhanced books of today, but if you're willing to get past the obvious sketchiness here you'll find a veritable gold mine of visual information. Take the overall layout & structure for example. In my opinion, this book's presentation easily rivals that of his more polished & refined work- Constructive Anatomy, which has a more awkward interplay between its words & pictures. The Human Machine moves rapidly & logically, building the figure with simple lines first, then showing how bones & muscles interact with each other & with the figure's simplified outline, to give an impression of the whole figure & its parts, all at once in a few detailed pages. It's this *overall* conception of the human figure that appeals to the many who give this work a chance. Bridgman applies all this to the figure's actions & mechanisms as well- it's not just about bones & muscles here, like so many anatomy books tend to be. And Bridgman's lines, though sketchy here, still tend to be an accurate record of the figure, worthy of study. He *usually* chooses his lines with the precision & beauty we've come to expect. But the overall lack of visual clarity here hurts; leaving this genius idea still somewhat unrealized.
Overall: The basic *point* of Bridgman's Human Machine is to help people to draw figures more convincingly, and even from memory. To a great degree, at least in my opinion, this book still succeeds in a very effective way...
P.S. This book is definitely *not* for beginners! Only *intermediate-level* artists need apply.