Hi Mary - I haven't seen any book exchanges in Tigaki for some years now.  I don't know where you are staying but many places keep books that have been left behind by other visitors for all to use. 

Hi Mary - Donna's apartments are really lovely, I am sure she will be able to show them to you whilst you are there.

Hi Donna -I knew you would have the solution to Mary's problem.  Our love to the family.

To my knowledge there isn't diving near Tingaki itself but if you look at website for Theokritos Travel.  I believe they do diving days if that is of any help.