As my single list of unread books was becoming unwieldy, I have divided it up into the following (loose) categories:
Eighteenth Century fiction and essays.
Eighteenth Century biographies and history.
London in the Eighteenth Century.
Historical novels set in the Eighteenth Century.
Historical novels set in other periods.
Fiction pre-Eighteenth Century
Fiction from the last 20 years (an arbitrary period and which overlaps with the previous category, but somehow I couldn't bring myself to create a 'contemporary' category).
Biographies and criticism of Shakespeare.
Volumes of poetry which I would like to read in their entirety (rather than my usual dip in/dip out method).
Books about books and reading (one of my favourite topics. There aren't many unread books in this category as I tend to gobble them down as soon as I buy them).
Biographies and memoirs of literary figures.
Essay collections (including volumes of collected reviews).