This is by no means an exhaustive list of all useful or helpful resources. These are resources I have personal experience with and have gotten something out of myself, for what that’s worth. Watch for updates as I keep looking at more resources.

Books:
“Mastery” by George Leonard
“The Way of Aikido” by George Leonard
“The Celestine Prophecy” by James Redfield
“Dojo Wisdom” by Jennifer Lawler
“Real Riding” by Perry Wood
“The BHS Book of the Natural Horse” by Sara Widdicombe
“Centered Riding” by Sally Swift
“The Classical Rider” by Sylvia Loch
“Classical Schooling with the Horse in Mind” by Anja Beran
“Tug of War: Classical versus ‘Modern’ Dressage” by Dr. Gerd Heuschmann
“Twisted Truths of Modern Dressage” by Philippe Karl
“True Unity” by Tom Dorrance
“Think Harmony With Horses” by Ray Hunt
“Racinet Explains Baucher” by Jean-Claude Racinet
Multiple Titles by Mark Rashid
“101 Jumping Exercises” by Linda Allen

DVDs
“If Horses Could Speak” by Dr. Gerd Heuschmann
“The Making of a Bridle Horse” (3-DVD set) by Buck Brannaman
“The Black Stallion” (movie)
“Colt Starting” with Ray Hunt
Various titles by Mark Rashid

Magazines:
“Eclectic Horseman” http://www.eclectic-horseman.com/

Kathleen uses saddles made by:

Dave Genadek: http://www.aboutthehorse.com
Meleta Brown: http://www.thefreedomsaddle.com
Antares: http://www.antares-sellier.com/index.php?vmcchk=1

Kathleen's chaps are made by:

Di Marietta: http://www.goldrushchaps.com/index.html