I can only speculate that this book is, as was one of the previous editions I've read, used and loved, is bound to provide an exceptional foundational education in the skill of technical (engineering design) drawing/drafting for those with the natural aptitude for freehand drawing. Readers will indeed learn about and develop precision drawing skills--whether drawing with instruments or computer.
The true value of this book is in its ability to guide and therefore transform the natural artist's raw talent into that of a professional grade design artist--capable of rendering technical depictions, representations, or designs, at any time, with little effort, and without error. As with learning to walk, this of course takes time, patience, and practice.
I have personally witnessed the struggles of many whom, having necessity to complete a course of study based upon this book, were ill-suited by their own admission for the discipline required of the eye, hand, and attention (or mind) as demanded by the capable sketch artist--to say nothing of the trained detail design drafter.
If realizing the instructional value of Technical Drawing, 12th edition, seems to come at great pain and effort, the obvious question clearly becomes one of aptitude for drawing. However, while the aptitude for drawing is extremely beneficial, proficiency in technical drawing can still be achieved by sheer tenacity.
Technical Drawing, 12th edition, as with previous editions, is therefore highly recommended for the tenacious engineer, designer and drafter. It has stood the test of time as a solid component of engineering design instruction in this nation's premiere academic institutions.