If the default fields are not enough for your e-Library you can create up to 5 custom fields. The custom fields are located in the Book Card and can be displayed in the Books View (Table View). You can also sort and search books by the custom fields.
Currently you can create only text fields. The custom field titles can be set in Tools -> Options.
When you entering values to custom field, the program shows you suggested values that begin with the same symbols.
You can also edit custom fields in multiple books at once using the Edit Books tool.