Start with what he is doing right now. Sebastian Cwilich runs Tertulia, a company that began life as a book-discovery app and has since grown into something stranger and more useful: a set of tools that listen to the internet's endless argument about books and try to turn it into a reading list you actually trust. The premise sounds obvious until you notice nobody had built it. As Cwilich put it at launch, for music, film, and art there are discovery engines everywhere - "there is, remarkably, no existing equivalent for books."
Tertulia launched on iOS on June 7, 2022. It scanned conversations and articles across the web - Twitter threads, critics' columns, the chatter of authors and strangers and culture-makers - and used machine learning to surface the titles that real people were talking about. You picked your genres and, more importantly, your trusted voices: critics, journalists, scientists, entrepreneurs, athletes, entertainers. Then it handed you five recommendations a day and got smarter as you tapped. Buying the book never required leaving the app, thanks to a partnership with Ingram Content Group and its catalog of fifteen million titles.
What if you could have all of the world's book conversations in one place?
— Sebastian Cwilich, on the idea behind Tertulia
The name is the tell. A tertulia is a Spanish and Latin American tradition - a regular gathering in a cafe or a living room where people meet to argue about literature, politics, and ideas. Cwilich, born in Argentina and the holder of a Columbia degree in both mathematics and Spanish literature, chose a word that fuses the two halves of his brain. The app is, in a sense, an attempt to scale a coffeehouse.
01The physicist who wandered off
Before the art and before the books, there was the lab. Cwilich moved from Argentina to the United States at the age of eight, studied math and Spanish at Columbia, then did graduate coursework in operations research and applied mathematics. From 1997 to 2004 he was a Senior Technical Staff Member at AT&T Labs - the storied research house - working with the kind of data and modeling problems that most people never see. It is an unlikely launchpad for a man who would later be photographed at art galas and quoted in Publishers Weekly.
But the through-line is there: Cwilich keeps walking into markets ruled by taste and gut feeling and asking what happens if you bring real measurement to them. Art. Books. The instinct does not change; only the inventory does.
02Charming the art world with data
In the late 2000s he crossed into the auction world, serving as VP and Commercial & Business Director at Christie's from 2007 to 2009, where he built the business plan for the house's new private-sales division. Then, in 2010, he co-founded Artsy, the platform that set out to connect collectors to art the way earlier sites connected listeners to music.
Over nine years as president and chief operating officer, Cwilich made many of the calls that turned Artsy into the largest online fine-art marketplace in the world. He pushed galleries onto subscriptions - a few hundred to a thousand dollars a month - instead of taking a commission on every sale, a quietly radical move in a commission-obsessed industry. He partnered with art fairs. He invested in a live-bidding platform that let collectors raise a paddle remotely at Christie's and Sotheby's from anywhere on earth. When he stepped back into an advisory role in 2019, he remained Artsy's second-largest individual shareholder, and went on to advise the Gagosian gallery on technology.
There is, remarkably, no existing equivalent for books.
— On why he built Tertulia
03Coming for the bookshelf
Tertulia is the third act, and in many ways the most personal - the Spanish-literature major finally building something for readers. He did not do it alone. He founded the company with Lynda Hammes, the former publisher of Foreign Affairs, and Robert Lenne, Artsy's longtime head of product and design, who works from Sweden. The engineering and data-science team sits in Buenos Aires, a deliberate nod to where Cwilich's own story started. The cap table reads like a hall of fame of consumer internet: AlleyCorp's Kevin Ryan led the round, with Bob Pittman of MTV and iHeartMedia, Sky Dayton of EarthLink, Jon Oringer of Shutterstock, John Ingram, Canvas Ventures, and FJ Labs all writing checks.
Startups, of course, do not move in straight lines. By 2025 Tertulia had leaned hard into a new product: tools for authors. Its flagship is a website builder that can spin up a complete author site - bio, reviews, contact, blog - from a single ISBN number, drawing on the data Tertulia gets through its Ingram partnership. Within months of its April 2025 beta it had drawn more than ten thousand accounts and over three thousand five hundred paying subscribers, with a free-to-paid conversion rate Cwilich called "off the charts" at 35 to 40 percent. The reader-facing dream and the author-facing business turned out to be two sides of the same page: help books find their people.
What stays constant across all of it is the man's refusal to accept that a market built on taste has to stay illegible. He took the opacity of the art world and gave it dashboards. He is taking the chaos of book talk and giving it a feed. Somewhere a physicist is nodding.
