I'm looking for a book regarding Tavel Guidance, information, about Venice Italy, Istanbul Turkey, and Santorini Greece.
Thanks for your question - that sounds like a fun trip!
Since the cities you're visiting are all in different countries we don't have a travel guide that covers them all together. But we have some titles that will be good for each location. Click on the links below and you will see our catalog listings for them. You can then log in with your library card and place a hold for any titles you're interested in, and have them sent to your branch to pick up.
Greece (We don't have a guidebook just on Santorini, but there should be some information in the books about Greece, specifically the one on the Greek Islands, since that's where Santorini is.)
I hope this helps. Have a good vacation.