Ecole de Cavalerie by Francois Robichon de la Gueriniere, one of the bibles of classical dressage, most famous for its introduction of the shoulder-in. According to Col. Alois Podhajsky, this is "the most revolutionary book on riding of all times. Its principles are still applied unaltered at the Spanish Court Riding School and may be seen there in daily use." by Francois Robichon de la GueriniereWilliam Steinkraus writes: "The first of the great 18th-century masterpieces, Francois Robichon de la Gueriniere's Ecole de Cavalerie, boasts not only a marvelous and ground-breaking text---a cornerstone of modern dressage---but also superb engraved plates by Charles Parrocel. La Gueriniere's work is still considered the equestrian 'Bible' of the Spanish Riding School of Vienna, and though it has only recently been translated word for word into English, it stands as an enduring landmark of equestrian literature."