The Organ Course by Benelux Musical Instruments is a comprehensive set of books tailored for organ players looking to improve their skills. Published in 1975, this workbook series covers various music theory concepts and techniques specifically related to the organ. Written by the renowned Benelux Musical Instruments, these books provide valuable insights and exercises for musicians looking to enhance their organ playing abilities. Perfect for both beginners and advanced players, this educational resource is a must-have for anyone interested in learning more about the organ and improving their musical talents.