Both books essentially have the same premise but explore it in different ways. The theory that intimacy is born out of telling what CL calls "the microscopic truth" where _all_ details are revealed.
"If you want a long-term relationship that's both close and creatively vital, you have to become emotionally transparent. To go all the way to ultimate closeness and full creative expression, you must eliminate all barriers to speaking and hearing the truth about everything." -- Gay Hendricks
But the truth is not accusing. You state what is going on within you. You describe your thoughts, feelings, your tensions, because that is what you own and that is what you can accurately describe. Everything else is probably just opinion or projection. Stating your feelings within is unarguable, it's your truth.
But it goes so much deeper. They talk about exploring reoccuring patterns where there is tension. I've noticed that everytime someone haltingly raises their voice, my shoulders automatically tense up. I think this is a pattern I learned very early on in my childhood from my dad screaming for no apparent reason. I am only now beginning to see it unfold.
Facing and telling the truth takes courage.
I've told my girlfriend that I find other women attractive. I told my girlfriend that I slept with someone else when we first started dating. In the end I believe she respects me more for telling her. At least the emotional "memory leak" has been cleaned up and I no longer have to suppress those thoughts or conjure up lies surrounding those circumstances.
"5 Secrets to Lasting Love" http://web.archive.org/web/20080316082737/http://www.lifecha...
Asides from being an enjoyable read, it provides an excellent framework and guide for how to have conversations about difficult topics successfully. It pairs well with the book "Nonviolent Communication"
These things take time and effort, but they really truly work.
[1] https://www.amazon.com/Conscious-Loving-Co-Commitment-Gay-He...