The Giant Schnauzer was created as a working dog.  With this being said, the Giant is very intelligent and take well to proper training.  This breed will create its own thoughts and and can become quite destructive if it's not given the proper training and socialization it needs.  Giants are eager to please its family and are very responsive to its owner.  To gain great control of this breed, respect is most needed from the Giant.  If your Giant respects you it will whatever it is asked.