What is Pilates?
"The Pilates method of body conditioning is a unique system of stretching and strengthening exercises developed by Joseph Pilates during his lifetime (1880-1967)."  (Brook Siler, The Pilates Body)

He called his system of exercise 'Contrology' , and, in his book 'Return to Life Through Contrology' (1945) he described it as "complete coordination of body, mind and spirit."   "Contrology develops the body uniformly, corrects wrong postures, restores physical vitality, invigorates the mind, and elevates the spirit."
He modified his mat work and developed apparatus to help clients achieve the fitness and strength required. 

Since his death his work has continued to be modified so there continues to be huge variety in what is taught...and in the training teachers receive.

Joe Pilates said: "In 10 sessions you'll feel the difference, in 20 sessions you'll see the difference, and in 30 sessions you'll have a different body".