I read cozy and historical mysteries, a bit of Paranormal/UF, and to mix it up, I read science and gardening books on occasion.
This was a lot of fun. Johnson has compiled book lists, but not the usual "you must read" sort. These are lists like Darwin's TBR, Oscar Wilde's bookshelf at Reading Gaol, the books on Scott's Discovery bookshelves (he had them in every room of the ship), books seen to be on Sheldon and Leonard's living room bookshelves in Big Bang Theory. Fun stuff like that.
Some of the titles listed are no longer to be found (Henry III's books, for example; probably hard to find if not impossible, and expensive to boot), some of them don't exist (books never written list - how did The Giant Rat of Sumatra not make this list?), some have yet to be written (the future library), and some of them are all to readily available and might be the death of any reader's TBR. Personally, I was doing pretty well until the very end, where he includes a list of books about books. My kryptonite! Aaahhhh...