Mr. Penumbra's round -the-clock bookstore UA

The global financial and economic crisis has turned the lives of San Francisco-based web designer Clay Jennon, and he was lucky enough to work as a night salesman at Mr. Penumbra's 24-hour bookstore. However, within a few days Clay realized that the bookstore was a rather mysterious place. There are a few customers here who come regularly but don't buy anything, just take something to "read" on the basis of some secret long-standing agreement with the mysterious Mr. Penumbra. Apparently, the bookstore is a cover for something much bigger, Clay decides and begins his investigation... An incredibly fascinating novel. "