Spam blocking software blocks all occurences of the letter 'p'. Sound familiar? Well - you could have been reading La Disparition - Georges Perec's cult classic novel, written without the use of the most common letter in the alphabet - 'e'. OR more recently Ella Minnow Pea which employs the disappearance of certain letters directly as a plot device.
Perec's novel is a little more discreet in employing the missing letter overtly in the storyline but it is almost there: The book is about a disappearance - and the missing person is called Anton Vowl.

Furthermore the english translation I read had a very elegant review from The New York Times Book Review on the book cover: "There is not a single E in this novel. That's right: no here, there where, when; no yes, no love, no sex!"