1930s vintage textbook Practical Business Administration, complete course in accounting, executive management

1930s vintage 'Co-operative System of Training in Practical Business Administration' Lesson Assignments and Instruction. This is published by the American Technical Society - I believe this might have been a study at home course, like the International Correspondence books of the same period. Looks complete (twelve 'volumes' in one), not marked up, red leatherette cover looks good.