Trust me, I'm a cultist. I love the HPL genre. If you are even here reading this, you could do worse than purchase this useful set if items. If you simply love the stories, the booklet and postcard photos will add to your mental picture. Oh, and the map. If you care about the man himself, then those items (and the map) will help your understanding. If you roleplay and, like me, like characters in depth, with wallets and pockets full of period bits like tourist guides, bus tickets, wallets and so on, this set will help. Oh, and the map, too.
I would buy this set just for the map, and then look at the other bits and celebrate the bonus. But the period map - which appears, much smaller, in "Night Black Deeds" - is a treasure. Maybe for historic, or nostalgic reasons, but some of us, whether planning an RPG or toying with a story idea set in the town, will love the detail of knowing lot numbers and locations of key buildings. I swear, an image search for "Providence 1930" could lead to a whole project, creating "Google Street View 1930", using this map.
To put it more succintly - this set is worth owning. It's fun, and it's fascinating.

Love the Providence pack. Hope to go soon.

Another home run prop/document set from the HPLHS. Beautifully produced and packaged as are all their ephemera. The map is so gorgeous and I love the inclusion of the booklet. Like being transported right to Providence of the period!