Redeemed, by Heather King.
King's first memoir, Parched, focused on her years of addicition (drugs and alcohol) and treatment, and ended with her entering sobriety. That memoir had little if any spiritual content, apart from the general God-stuff of AA.
But this is a total spiritual memoir, as King explains how she found God in the most unlikeliest place she could imagine: the Catholic Church. Her expressions of love for Mary and the Eucharist may make some uncomfortable, but whoever can get past that will find a delightful and extremely well-written book. The sections describing her newfound love for the church's teachings on sex and abortion, for example, are worth finding.
I am personally a sucker for conversion stories of all types, and this one is written by someone with a humbling transparency and real ability to spin a compelling tale. I was hooked from the first page and enjoyed it all the way to the end.