Titles in this case mean titles of address–Mr., Mrs. Lady, Duke of, Sargent, General, etc. Cathy was limited to 10 books due to the rules of the game. I track my reading so went back quite a ways as I became fascinated by how frequently this type title featured in my reading history! Cathy and I had two titles in common-–Miss Pettigrew Lives for the Day and Entertaining Mr. Pepys.
I omitted “Professor” and “Headmaster.” I also skipped royal biographies and one other Mrs. Lincoln book. I’ve read the vast majority of these, the others were found on my TBR.