The Last Revelation of Gla'aki (2013) by Ramsey Campbell

The Last Revelation of Gla'aki (2013) by Ramsey Campbell: Academic librarian Leonard Fairman travels to the small English coastal town of Gulshaw to collect the rarest set of books in the world -- a complete set of The Revelations of Gla'aki, a mystic narrative thought to have been lost. 

The curiously...puffy... townspeople are fairly cheery and helpful, but they will lead Fairman on something of a tour of the town in order to retrieve each volume from a different citizen.
Arkham House  released the precocious Campbell's first published volume, The Inhabitant of the Lake, in 1964, when he was 18. Nearly 50 years later, he returns to Gla'aki, one of the Lovecraftian entities introduced in that book and mentioned in many of his stories and novels over the years.

While Gulshaw is a Town With A Secret, one of the most venerable of horror tropes, it's the sort of weird town that happily welcomes the outsider. Welcomes him so much that everyone he meets seems to know his name and his mission. The food must be good in Gulshaw because everyone seems to have developed a weight problem. But everything Fairman eats has an odd sort of consistency. It's not often that mouthfeel comes into a horror story.

The horror here builds gradually -- like the attentions of the town itself, to quote a Stephen King title, it grows on you. And in you. There are echoes of H.P. Lovecraft's "The Shadow Over Innsmouth" here, but as noted above, the people of Gulshaw aren't inimical to visitors. Indeed, they're very friendly to everyone who visits. There's so much more to see in Gulshaw, you see. Or sea. Recommended.