Leaving the Fold - information - this book by Dr. Marlene Winell was my first introduction to the notion of religious trauma. It is primarily focused on a particular set of experiences (fundamentalist/evangelical christianity) which are directly relevant to my own life, but it does offer some helpful insights for those in other situations as well. I will note that while it informed several major steps in my own recovery process, this work is fairly narrowly focused, very much white, and rather cis-het-binary-normative in style.
Down at the Cross by James Baldwin - information - I found this essay (published as part of the linked book, The Fire Next Time) to resonate incredibly well with me, despite coming from a very different lived experience than my own. There are quite a few parallels between Baldwin's relationship with the christian religion and mine. Aside from its personal relevance to me, it's a pointed and moving exploration of how deeply entangled certain forms of religion really are with certain forms of oppression.