The citation information for this 16-page pamphlet is Charles Bruning Company, Inc., Instruction Manual for Bruning Slide Rule No. 2401 (New York, 1944). The cover notes that the company had applied for a patent on a slide rule indicator, but no such patent has been found. The manual begins with the claim that results on model 2401 were significant to three digits. After explaining the parts of a slide rule, the manual divides the process of learning to use a slide rule into twelve steps, each of which are discussed with examples, solutions, and exercises in the remainder of the pamphlet. This manual was received with 1991.0445.03.