Theory of Operations includes:  Principles of flight, airframe, landing gear, powerplant, rotor systems, drivetrain, hydraulics, instruments, electrical, fuel systems, flight controls, utility systems, environmental controls, hoist and wenches/cargo handling system, aux power, mission equipment, and much more.  In a convenient mini size.  Approx. 7" x 8" and spiral bound.  All materials are current when shipped.