The Giant Schnauzer is the largest of the three breeds. Giants were developed in the Wurttenberg and Bavaria sections of Germany where they were utilized by farmers, butchers, and breweries. It is said that during World War I the breed was recognized in Germany for its intelligence, trainability and became one of the breeds used for police work.
If you are looking for a companion that gives you all of their heart, here it is. In my opinion all three of the Schnauzer Breeds have an unwavering loyalty to their families, but when the a Giant shows up, all eyes are on them, they have a commanding presence and everyone wants to meet them. Simply put, they are a great dogs if properly trained but can be a complete train wreck if left to their own devices. They do better if they can be with their humans, they are definitely a velcro dog. Due to their intelligence and size they can be a handful. Believe me they learn how things work very quickly, whether you teach them or they teach you. For more info on the breed visit, http://www.akc.org/breeds/giant_schnauzer/index.cfm