[BetterRed]

@Sarmat - create a custom column of type Date, #read_date/Read Date, then when you F2 on an empty Read Date cell it will autofill it with current date (and time).

When a book is first created, Calibre sets the builtin date/Date column to the current date (and time). As far as I know calibre makes no further use of the column, and given that it's an editable column (unlike last_modified/Modified) it is legitimate to repurpose it. However, as you've noticed if it's cleared, a subsequent F2 will autofill it with the date (and time) that calibre/python regard as the beginning of time - 1st of January CE 101.

I've used the date/Date column as my 'Read Date' ever since I started to use calibre in March 2012 - I use F2 '-' when I add a book, and F2 '=' when I've read it. I have no reason to want a date added column. If I wanted it, the create data on the book folder would be good enough for me - but that's only available on Windows file systems.

BR