"A search and rescue operation is under way, including a police dog and a drone searching hard to reach areas.
A helicopter is flying from Athens to assist, Symi's deputy mayor told BBC News.
Greek Police said Dr Mosley left his wife on the beach and set off on a walk to the centre of the island on Wednesday.
His phone was found at the place he was staying at with his wife, who reported him missing, a police spokesperson told BBC News."
I hope they find him safe and well...