Out of curiosity about the Carthusians, I (a Catholic layman) picked up ‘First Initiation into Carthusian Life’. I was struck by exactly what you point out here: it goes surprisingly (to me) straight to the point on cultivating an interior life that can lead to contemplative prayer. Cells and ambulatories and antiphonals are covered but they aren’t what it’s all about.

Thanks for your posts. Looking forward to what else you have to share.