New? You could get a 1960's-era Bruce Tegner book that says the same thing. Since before World War II, Col. Rex Applegate, Fairbairn & Sykes and Brad Steiner have stated in one form or another that life-and-death combat is about nothing less than "Kill Or Be Killed."
The trick: how to AVOID being penetrated as well as DELIVER your weapons against a non-compliant aggressor who is ALSO trying to defend himself. It is all about adaptation and improvisation. Train only to hit and you can't adapt to a changing defense. Train only specific defenses and you will be overwhelmed. Train primarily to blend, flow, improvise and adapt--and you will be able to adapt.
That is the key to surviving violent chaos and that is the gift GM Perkins offers.