Donaldson presents resource guarding as a normal, adaptive behavior and rejects notions that resource guarders are not \"nice\" dogs or are \"dominant aggressive\". Instead, she focuses on a behaviorist approach to conceptualizing and remediating such behavior.
In a nutshell, this primarily involves classically counter-conditioning a \"conditioned emotional response\" where an owner's approach is associated with high-value food treats, rather than representing a threat of loss or punishment. Initially this is done in the presence of little provocation, but incremental advances proceed until the dog can happily be approached when in the presence of whatever he formerly guarded most fiercely.
Anal retentive to a fault (and I mean that as a compliment in this context), Donaldson does an excellent job of breaking down forms of resource guarding behavior into detailed, progressive increments. In order to teach a dog to accept having its mouth opened, for example, she lists 60 separate steps - beginning with touching the dog's rump for a single second. It takes 27 steps before one even touches the dog's head.