1795 Concordance

The Dark Shadows "Concordance" books are pretty impressive by any standard. I own two, one of which is spiral bound, the other published with perfect binding. These books are incredibly detailed episode guides, a concept that Dark Shadows fans never benefited from through mainstream publishing. The Concordance series is also richly illustrated (an example page from the 1795 Concordance can be seen above) with both color and black and white line art.

It's a wonder these books were never snapped up by mainstream publishers and reproduced (though probably in a heavily edited format) as a single-volume episode guide. It sounds like the sort of thing Katherine Leigh Scott's Pomegranate Press would be interested in.