"It is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change."

"The expression of the emotions in man and animals is a study of the utmost interest."

"In the long history of humankind (and animal kind, too) those who learned to collaborate and improvise most effectively have prevailed."

"The world will not be inherited by the strongest, it will be inherited by those most able to change."

"The greatest discovery of all time is that a person can change his future by merely changing his attitude."