When was "To Kill A Mocking Bird" first written ? Is there a difference between that and the first publication

Answer 1

Yes there is a difference. It may take some time for a book to be written and, equally it may be some time after the book has been completed that it actually gets published.

In the particular instance you cite, "To Kill a Mockingbird" was written by Harper Lee in the late 1950s and was first published in 1960. In this case not a great difference in the time of writing and the first publication date.