Slitherine

We already have 3 army list books out, and we know what 4-7 are going to be. We also know that there's a Dark Ages book and a Biblical book being discussed for next year. Do we yet know what book 8, 9 and 10 etc will be? Is book 8 the Dark Ages one, for example, or Biblical, or something else entirely? What other books are on the table apart from Dark Ages and Biblical in the future?

My understanding is that book 8 will be dark age Europe, book 9 will be Biblical and after that I really don't know any schedule.

Gaps in the current and planned lists include Feudal Europe, The far East and the Americas for a start.