Don't be fooled. This initiative is not about #OpenAccess books. It's from publishers and authors who generally don't want OA for books. It's about free events about books (good) and transparency about the book industry (good), but not OA for books.
https://www.publishers.org.uk/the-pa-ba-and-aaa-join-together-for-openbooks-a-new-initiative-to-reach-the-next-generation-of-book-industry-talent/

PS: I can't tell whether the name is a marketing mistake by people unaware that "Open Books" is already a thing, and a thing in tension with what they are doing, or whether it's #OpenWashing.

The PA, BA and AAA join together for OpenBooks – a new initiative to reach the next generation of book industry talent

The Publishers Association, Bookseller’s Association and Association of Author’s Agents are proud to collaborate on the development of OpenBooks – a brand new series of free, accessible online events primarily targeting young talent from underrepresented backgrounds.

Publishers Association
@petersuber My local library has a long standing event series called "Open Books, Open Minds" that has nothing to do with OA. I think the defensible term is "Open Ebooks"; "Open Books" already has too many meanings to be a good term of art. In other words, I'm afraid "Open Books" was a thing long before OA.