This special 40th anniversary paperback edition combines Vol. 1 and Vol. 4 into this 630-page paperback edition to commemorate the discovery in 1976 of the State-Space Averaging Method, the new Cuk-type converters and the general magnetics methods of Coupled -Inductors and Integrated Magnetics. Many generations of engineers used this material as one of the first textbooks to get into emerging field of Power Electronics and learn the basics. One of my many PhD students, a professor of Power Electronics for many years, recently commented: "This Power Electronics Series represents a Big Bang in the History of Power Electronics " Another well respected industry expert commented: "You should all read everything that Dr. Cuk has ever written ". This material is essential for the understanding of my upcoming books: Volume 5 titled Power Electronics: A New Beginning and Volume 6 titled Power Electronics for the 22nd Century. The State-Space Averaging and Cuk converters presented here led to critical re-evaluation of the conventional buck, boost, flyback, forward, bridge type and LLC converters which dominated industry for last 60 years The time has now come for them to be replaced by new Power Electronics System Technology based on three new Resonant/PWM type switching methods and related novel converter topologies and new magnetics structures The present edition is a key basic stepping stone toward that goal.