My most humble and sincere thanks to:

As always, first and foremost, my editor and close friend, Jason Kaufman, for his dedication and talent … but mainly for his endless good humor.

My extraordinary wife, Blythe, for her love and patience with the writing process, and also for her superb instincts and candor as a front-line editor.

My tireless agent and trusted friend Heide Lange, for expertly navigating more conversations, in more countries, on more topics than I will ever know. For her skills and energy, I am eternally grateful.

The entire team at Doubleday for its enthusiasm, creativity, and efforts on behalf of my books, with very special thanks to Suzanne Herz (for wearing so many hats … and wearing them so well), Bill Thomas, Michael Windsor, Judy Jacoby, Joe Gallagher, Rob Bloom, Nora Reichard, Beth Meister, Maria Carella, Lorraine Hyland, and also to the unending support of Sonny Mehta, Tony Chirico, Kathy Trager, Anne Messitte, and Markus Dohle. To the incredible people of the Random House sales department … you are unrivaled.

My sage counsel Michael Rudell, for his pitch-perfect instincts on all matters, large and small, as well as for his friendship.

My irreplaceable assistant Susan Morehouse, for her grace and vitality, and without whom all things descend into chaos.

All of my friends at Transworld, in particular Bill Scott-Kerr for his creativity, support, and good cheer, and also to Gail Rebuck for her superb leadership.

My Italian publisher Mondadori, especially Ricky Cavallero, Piera Cusani, Giovanni Dutto, Antonio Franchini, and Claudia Scheu; and my Turkish publisher Altin Kitaplar, particularly Oya Alpar, Erden Heper, and Batu Bozkurt, for the special services provided in connection with the locations in this book.

My exceptional publishers around the world for their passion, hard work, and commitment.

For their impressive management of the London and Milan translation sites, Leon Romero-Montalvo and Luciano Guglielmi.

The bright Dr. Marta Alvarez González for spending so much time with us in Florence and for bringing to life the city’s art and architecture.

The peerless Maurizio Pimponi for all he did to enhance our visit to Italy.

All the historians, guides, and specialists who generously spent time with me in Florence and Venice, sharing their expertise: Giovanna Rao and Eugenia Antonucci at the Biblioteca Medicea Laurenziana, Serena Pini and staff at the Palazzo Vecchio; Giovanna Giusti at the Uffizi Gallery; Barbara Fedeli at the Baptistery and Il Duomo; Ettore Vito and Massimo Bisson at St. Mark’s Basilica; Giorgio Tagliaferro at the Doge’s Palace; Isabella di Lenardo, Elizabeth Carroll Consavari, and Elena Svalduz throughout all of Venice; Annalisa Bruni and staff at the Biblioteca Nazionale Marciana; and to the many others whom I’ve failed to mention in this abbreviated list, my sincere thanks.

Rachael Dillon Fried and Stephanie Delman at Sanford J. Greenburger Associates for everything they do both here and abroad.

The exceptional minds of Dr. George Abraham, Dr. John Treanor, and Dr. Bob Helm for their scientific expertise.

My early readers, who provided perspective along the way: Greg Brown, Dick and Connie Brown, Rebecca Kaufman, Jerry and Olivia Kaufman, and John Chaffee.

The web-savvy Alex Cannon, who, along with the team at Sanborn Media Factory, keeps things humming in the online world.

Judd and Kathy Gregg for providing me quiet sanctuary within Green Gables as I wrote the final chapters of this book.

The superb online resources of the Princeton Dante Project, Digital Dante at Columbia University, and the World of Dante.

All artwork, literature, science, and historical references in this novel are real.

“The Consortium” is a private organization with offices in seven countries. Its name has been changed for considerations of security and privacy.

Inferno is the underworld as described in Dante Alighieri’s epic poem The Divine Comedy, which portrays hell as an elaborately structured realm populated by entities known as “shades”—bodiless souls trapped between life and death.

I am the Shade.

Through the dolent city, I flee.

Through the eternal woe, I take flight.

Along the banks of the river Arno, I scramble, breathless … turning left onto Via dei Castellani, making my way northward, huddling in the shadows of the Uffizi.

And still they pursue me.

Their footsteps grow louder now as they hunt with relentless determination.

For years they have pursued me. Their persistence has kept me underground … forced me to live in purgatory … laboring beneath the earth like a chthonic monster.

I am the Shade.

Here aboveground, I raise my eyes to the north, but I am unable to find a direct path to salvation … for the Apennine Mountains are blotting out the first light of dawn.

I pass behind the palazzo with its crenellated tower and one-handed clock … snaking through the early-morning vendors in Piazza di San Firenze with their hoarse voices smelling of lampredotto and roasted olives. Crossing before the Bargello, I cut west toward the spire of the Badia and come up hard against the iron gate at the base of the stairs.

Here all hesitation must be left behind.

I turn the handle and step into the passage from which I know there will be no return. I urge my leaden legs up the narrow staircase … spiraling skyward on soft marble treads, pitted and worn.

The voices echo from below. Beseeching.

They are behind me, unyielding, closing in.

They do not understand what is coming … nor what I have done for them!

Ungrateful land!

As I climb, the visions come hard … the lustful bodies writhing in fiery rain, the gluttonous souls floating in excrement, the treacherous villains frozen in Satan’s icy grasp.

I climb the final stairs and arrive at the top, staggering near dead into the damp morning air. I rush to the head-high wall, peering through the slits. Far below is the blessed city that I have made my sanctuary from those who exiled me.

The voices call out, arriving close behind me. “What you’ve done is madness!”

Madness breeds madness.

“For the love of God,” they shout, “tell us where you’ve hidden it!”

For precisely the love of God, I will not.

I stand now, cornered, my back to the cold stone. They stare deep into my clear green eyes, and their expressions darken, no longer cajoling, but threatening. “You know we have our methods. We can force you to tell us where it is.”

For that reason, I have climbed halfway to heaven.

Without warning, I turn and reach up, curling my fingers onto the high ledge, pulling myself up, scrambling onto my knees, then standing … unsteady at the precipice. Guide me, dear Virgil, across the void.

They rush forward in disbelief, wanting to grab at my feet, but fearing they will upset my balance and knock me off. They beg now, in quiet desperation, but I have turned my back. I know what I must do.

Beneath me, dizzyingly far beneath me, the red tile roofs spread out like a sea of fire on the countryside, illuminating the fair land upon which giants once roamed … Giotto, Donatello, Brunelleschi, Michelangelo, Botticelli.