Here is a good source of information. There are interviews and articles by Tony Blauer and his self defense system.
There is some great information on fear management and insight into why the S.P.E.A.R. system is based on upon human genetic responses to violence and danger. The best thing about the system is that it is geared towards what are bodies want to naturally do in a self defense situation. If we flinch when something goes towards our head or body automatically, then how do we use that for our advantage, where do we go from there. Converting that flinch is the key while engaging the attacker until the aggression is over, or you can flee. Another great aspect of the system is that as it deals with what takes place before a confrontation starts, how it starts, how to position yourself before, what mindset you should have, how to diffuse or deescalate a confrontation, how to look for pre-contact clues and adopting a NVP (non violent posture) that is really a fighting stance in disguise. The best part is that is doesn’t matter what style you currently train in or have in the past as it does not interfere at all. The system deals with before and during the initial attack, from there you can do whatever you feel is best for you. If you have no prior training then tools and weapons (strikes,elbows, knee strikes,rakes etc…) to use can be taught easily.