* A misremembered title: Perhaps you're thinking of a different book with a similar name.
* A fictional work: It's possible this is a title of a fictional work, a short story, or a fan-fiction.
* An unpublished work: It's possible someone has written such a diary but hasn't published it.
To help you find the information you're looking for, please provide more context:
* Do you remember any other details about the work? Author, genre, where you might have seen it mentioned?
* Is this a specific book you're looking for? Or are you looking for information on the topic of nudist diaries in general?
With more information, I might be able to help you find the book or information you need.