Dan Brown | Inferno

NBC

Dan Brown's Inferno is another globe-trotting, world-saving adventure — and a chance for readers to ponder a new set of mathematical and scientific puzzles.

The Italian poet Dante Alighieri was, if anything, more of a numbers freak than Dan Brown: Who else would write a three-book masterwork consisting entirely of three-line stanzas? Each book is divided into 33 cantos — plus an extra one in Dante's Inferno, to make 100 cantos in all. The verses are riddled with references to threes, sevens, nines and other numbers with mystical meanings.

Numbers and codes have played a part as well in the buildup to the release of Inferno. Even the publication date is a puzzle: Greg Taylor, author of “Inside Dan Brown’s Inferno,” noticed that if you reverse the American date notation, 5-14-13, you come up with the first five digits of pi (3.1415). Brown’s publishers later confirmed that the date was chosen for just that reason.