This is a rare two-book set by Ira Ritow from Dolphin Books, including 'Advanced Servo-Mechanism Design: A Detailed Study of the Theory and Practical Application of the Principles of Automatic Control' and 'A Servo-Mechanism Primer: An Introduction to the Theory and Design of Automatic Controls.' Both books are first edition printings from 1963 in English, published by Doubleday & Company, Inc., Garden City, New York. These volumes cover foundational and advanced principles of automatic control theory, featuring original illustrations, diagrams, and comprehensive text. The books are in good condition with clean pages and intact bindings, perfect for collectors, engineers, and students of automation or electrical engineering. Both titles are highly sought after and are key references in the field, making this set a valuable addition to any technical library.