According to the former page http://www.chaosium.com/cthulhu/fiction/6025.shtml (found via http://web.archive.org):
by T. Marsh & P. Marsh
Call of Cthulhu Fiction
A Cthulhu Mythos Novel
Many authors have told of the dangers of the Cthulhu Mythos and how its malign influence twists and corrupts scholars and ordinary people alike - and threatens our world. But imagine perceiving the Mythos from the Inside. Would it still be horrifying, still be a menace to all life, and still be strange enough to provoke insanity? Or are many humans culturally Insane? Join the search for Clara Boyd! Visit Miskatonic University! Follow the investigations of the Bolumbo Detective Agency! Learn from the Yaggya! An entertaining and often challenging novel whose points of view frequently change.
http://www.chaosium.com/callofcthulhu/cocfiction_list.html simply lists it as "cancelled".
The book was eventually published by 1st Books Library.
It is an expansion of Glimpses of Other Nations (itself a compilation of shorter pieces) and The Worm Shall Ye Fight, originally self-published by the authors.