By my count 830, just over 50% unread. That includes kindle (but thats a small amount) and I count a book that contains multiple full stories, like a set of 3 Agatha Christie novels in one book, I would count that as 3 separate books.

The vast majority of it is non-fiction history. Biggest category within that being the First World War at 130ish books (including some fiction) taking up 4 and a half big shelves (probably a full 5 shelves by the end of next year). Other big categories are British history, Russian history, German history, random history where I don't have enough on a topic to justify having a seperate section, Second World War (probably my worst in terms of read vs unread, lots of cheap WWII books in British charity shops) plus some other small categeories.

Fiction wise its a mix of old fashioned murder mysteries, seperate section for Agatha Christie, historical fiction, and a small amount of fantasy and sci-fi (but a big Discworld / Terry Pratchett pile seperatly)