This thesis investigates the specific treatment of the clarinet family in selected nineteenth-century treatises that were written in Paris, or were influenced by their author's experience in Paris. Four works by Georges Kastner, Hector Berlioz, and Francois Gevaert have been selected. These influential treatises were written and revised between the years 1836 and 1885. The primary purpose of these treatises was to serve as instruction manuals for students of musical composition. Demonstrating a strong unity in information they also diverge on various points, reflecting the changing state of instrument manufacture, performance abilities and aesthetic requirements demanded by composers.