Dr. Daina Taimina

available as open source at Project Euclid
"This book remains a treasure, an essential reference. I simply know of no other book that attepts the broad vision of geometry that this book does, that does it by-and-large so successfully, and that pays so much attention to geometric intuition, student cognitive development, and rigorous mathematics." - Judy Roitman, University of Kansas

"I found this text to be a wonderful, fresh, and innovative treatment of geometry. The Moore method of study by doing and involving the student works very well indeed for this subject." - Norman Johnson, University of Iowa

David Henderson Experiencing Geometry part 1

David Henderson Experiencing Geometry, part 2