It changed my life, I know that much. There's that chart in there that shows how our obsession progresses from trying to get him to change (and it's not necessarily just alcoholics), all the way to a state where we're physically ill and he's our only focus. When I first read it I cried and cried over that chart.
The other books that I loved and really helped me were the Toby Rice Drews "getting them sober" books. Codependent no More is my gold standard but women who love too much and getting them sober kind of dragged me through the early days.
Hugs,
SL