I have two custom column although it could probably be done in one. I have a yess/no column where I check off books I have read. I like this because it is easy to see and sort on.
I have another column text, with a set of permitted values where I three values. Read, Must read and maybe read, or blank if undecided.
Must read is my favorite authors/series, Read is for books I know I will like, Maybe read is for books that sound sort of interesting and blank means haven't a clue
How I use this and maintain it is a bit bizarre as I try to track books I have read and books I want to read that are available in print and ebook, as well as books I have.
It is in a constant state of flux whenever I get really bored
Helen