Years before the publication of The Da Vinci Code, fans of Brown's novel Deception Point might have noticed a seemingly random series of numbers and letters on the last page of that book: "1-V-116-44-11-89-44-46-L-51-130-19-118-L-32-118-116-130-28-116-32-44-133-U-130."
While sane readers probably assumed that a mouse got stuck in the gears of whatever giant printing press spits out Simon & Schuster paperbacks, crazier fans may have checked to see what would happen if you replaced each number in the sequence with the first letter in the corresponding chapter in Deception Point. If you did that, you would have discovered the letter sequence "T V C I R H I O L F E N D L A D C E S C A I W U E" -- which you might recognize as also complete gibberish. But Brown's crazy fans didn't decorate their sheds with newspaper clippings and jars of urine because they're quitters. Those fans would have noticed that there are 25 letters, which is a square-able number, and realized that when you arrange those letters in a five-by-five square, you get:
T V C I R
H I O L F
E N D L A
D C E S C
A I W U E
... which, when read from top to bottom by column (instead of left to right by row like you just did), reveals the message: "THE DA VINCI CODE WILL SURFACE."
Of course, this being two years before the phrase "Da Vinci Code" meant a goddamn thing to anyone, they would have been just as likely to wonder who Dav Incico was and how exactly he was mixed up in the sinister sounding Dew-Ill Surface. Which makes it all the more impressive that Brown got away with crazying up the last page of his book two years before it meant anything.
When The Da Vinci Code finally did surface as promised, the book's dust jacket was riddled with crazy cyphers.
"The Greek letter delta gets its shape from a hand raising the middle finger. I think the meaning here is obvious."