"Further reading" 

Hallo Wikisjt3: I've seen some discussion on various talk pages about this. (,  - just to run this past your eyes too.)

The church already has an article, at St. Mary of the Visitation Catholic Church (Huntsville, Alabama), as it's on the NRHP. (It's unfortunate that the book title doesn't identify which "St Mary of the Visitation" church it's about, but I traced it with a bit of detective work: Alabama was mentioned somewhere, there's a helpful disambiguation page at St. Mary's Church, there's only one listed in Alabama, and the church website confirms this book as being about this church.)

I've added this book as "Further reading" (sourced from the Worldcat record), which I think seems appropriate even though the book does not see WP:NOTABLE enough to have its own article. Anyone wanting to learn more about the church now knows this book exists, and can link the isbn to trace the catalog record in Worldcat and perhaps elsewhere. 

It may be that there is some more information which could usefully be added to the article about the church, sourced to the book (as far as I  know the book would qualify as a "Reliable source"). The article at present is entirely about the architecture of the building, not the history of the church as an organisation. In adding anything, remember to write in your own words and not copy the text of the book, which would be a breach of copyright. And please remember not to overwhelm readers with too much detail: less can be more if it lets the most important aspects shine out. D