Not sure how these books have flown under my radar for so long…

https://en.wikipedia.org/wiki/Cult_Movies_(book)

https://en.wikipedia.org/wiki/Cult_Movies_2

https://en.wikipedia.org/wiki/Cult_Movies_3

A quick blurb about the author from his Wikipedia entry:
(https://en.wikipedia.org/wiki/Danny_Peary)
Peary's Cult Movies trilogy, along with other touchstones such as Michael Weldon's Psychotronic Video magazine and books, helped establish a foundation for critical analysis of low-budget genre movies. As the Austin Film Society wrote,
“There is what we might consider the Danny Peary faction. An excellent writer, Peary lionized a particular kind of “cult" criticism in his multiple volumes of the Cult Movies books. Never dismissive, Peary celebrates these films for their unique qualities and their advocacy of outsider voices. Peary is a fan of the subversive and the humanistic and the books are essential reading for anyone interested in what lies just outside the bounds of the canon.”