SET @tablename = N'authors'

What 's that means N'?

Thanks.

Hi,
normally this has to do with explicitly converting the following string value to a Unicode standard. I think the N stands for National language character set.
You can read much more about the reasonings in the following:
01 (http://support.microsoft.com/default.aspx/kb/239530)
02 (http://msdn2.microsoft.com/en-us/library/aa902644(SQL.80).aspx)
HTH
Good luck