Unit sales are flat to slightly up, Tamblyn said, but the trade has grown good at selling more to enthusiasts while people who bought one or two books a year drift off. The traveler now has Wi-Fi on the plane, and the beach reader is scrolling. Biesemeier added that many lost readers never knew they could be readers. He cited a drop of about a third of German book buyers in a decade (his figure).

Marketing is a mix of product, format, channel, time, target group and price, Biesemeier said, and the industry still thinks product first. Cox teaches students to begin with who the reader is and where that person reads, watches and listens. Biesemeier's equation: reach plus relevance equals conversion.

After three years in audiobooks, Biesemeier saw most sales come from older titles. A book that is ten years old is new to someone discovering it on Spotify. Tamblyn made a similar point about independent authors, who ask how to revive a book a year after launch, while traditional publishers move on after about six months.

Each retailer serves a different audience, and the best-selling books on each channel show different patterns, such as mobile-first or audio-first, older or younger. One metadata set for all may cost "only five percent", Biesemeier said, but it is five percent. Retailers should send this knowledge back to publishers, who usually lack it.

Kobo expected early adopters, as with music and video. Instead, people in their fifties, sixties and seventies led the move to digital reading, drawn by adjustable fonts, light devices and no trips to the store, Tamblyn said. Populations are aging in Europe and Japan and increasingly in North America. Kobo co-produced a report on longevity publishing.

A reader whose print books feel too small may stop reading if they do not switch to digital, Tamblyn explained. Someone with macular degeneration or cataracts who does not move on to audiobooks is lost again. He saw no publisher strategy for this and wants lifelong readers "as opposed to lifelong as long as it's easy".

Publishers find and develop authors, while retailers close the gap to the customer, Tamblyn argued. Direct-to-consumer tends to go badly because it needs different reflexes and economics, and getting a customer through the door is expensive. Biesemeier pleads for funnel-based thinking, citing Dyson's newsletter revenue targets. The two views differ in emphasis.

Publishers now hand authors a to-do list of blog, Instagram and mailing list, Tamblyn said, so the gap to self-publishing feels smaller. Independent authors see day by day what an ad or newsletter does, and authors increasingly flip back and forth. Zeltner, who has published two books, said he never had access to such data.

Audio helps claim time for books, Tamblyn said. Germany is deep into audiobooks, France stays "all text all day long". A book, in his view, is the safest place in a world of fragmented attention, and publishers should create emotional engagement, not publish into a "TikTok shaped box". Biesemeier countered with micro dramas of 90 seconds, showing that context and format matter.

There have always been more books than anyone could read, Tamblyn said, but machine-generated text raises the value of curation. Biesemeier asked whose job it is and wants publishers to help retailers. For music, he cited 75,000 new titles a day, half AI (his figure). Tamblyn warned that data cannot design a book, and AI output is "the average of all of the things that have worked before".