Boyd's E-M Theory

Hello folks!

I am just reading a book about John Boyd, the inventor of the so-called E-M theory (E-M for Energy Maneuverability), which is said to change the whole fighter business of the USAF in the 1960 and was basis for fighters like the F-15 and F-16.

The thing is, I don’t really understand what this theory is about. As the book is rather narrative than scientific it is more guesswork to understand.

What I learned so far is that Boyd used SEP (Specific Excess Power) to evaluate aircraft performance.
SEP = [(Thrust – Drag)/Weight] * (inertial)Speed

Another element of his theory seems to be total energy management, this thing that says you have to go nose-down shortly to have the the quickest climb.

Can anybody enlighten me:

Thanks for information.