Any book on OCD, other than the garbage pumped out by "gurus" which can be nonsense (and Phil does have one of these and I know it's very light on anything OCD because I have read
), is going to cover the basic cyclical relationship of triggers, reactions, obsession-to-compulsion, negative behaviours, etc. You can't explain OCD without it. It should be touching no more common issues that cross anxiety barriers such as core beliefs, rules & assumptions and how to modify them, etc. Perfectionism should be covered as it's a big part of OCD and other obsessive style disorders.
I think Phil is a very literal kind of person who almost needs to see a physical A-B process he can follow. Unless he buys books purely describing his scenarios, which may mean several or not even possible to cover it all, I doubt he will find this. But this is where the therapist can tailor for him, and didn't she do certain things like cards detailing what was a normal range of actions to a scenario?
There are nuances between these themes, and OCD is split into categories of mostly obsession, mostly compulsion or mixed but it's true that the majority works for everything. That's why doctors don't care so much for themes and more for what's underneath them. They know treating a theme doesn't necessarily treat what's underneath.
Contamination books will exist, OCD was always stereotypes as cleaning. Perfectionism most likely will too, books outside of OCD will also talk about obsessional behaviour as it's just an extension of normal personality. Solipsism I think would be out there but not books about it as a theory, books about it in terms of mental health. But a lot of this is going to be repetitive and can be found free online anyway.