Firstly, I’ve flow with 29 flight instructors in the past decade in
both glider and powered airplanes while working on a variety of
training and goals. Several were very good in one way or another, be
it a spotless technique, a devotion to safety, making the student at
ease in the cockpit, or conveying the physics of flight in an
accessible manner. A few others may have been good pilots, but
horrible instructors. I have also read a number of the books mentioned
in this discussion thread and have learned much from them.

But I have to say that Russell Holtz not only combines all of the
qualities mentioned above, but also instructs in a very systematic
fashion that prepares the student-pilot to succeed in every step of
the flight training process. I am working with him towards my CFIG
rating and am impressed with the level of thought and preparation he
has put into his syllabus. His books, Glider Pilot’s Handbook of
Aeronautical Knowledge and Flight Training Manual for Gliders, reflect
these qualities, are very comprehensive in their content, and are
pedagogically skillful. Though I believe in the value of reading
different texts, Russell’s books offer the best soaring course to
primary and transition pilots.

Dan