Why it’s on the list: A few years ago I did just this. It took me a whole day (I have a lot of books!) but it was great because I could find what I wanted straight away and knew what I had by any given author. Then I moved house and the books got packed and unpacked and mixed up, and I’ve never got round to sorting them out again.

How/when I’ll judge this task to be completed: When my bookshelves reflect this slightly anal wish.