Here is a beautiful example of a lockable vintage travel diary by Samuel Ward of Boston, Massachusetts. It is unused, still in its original packaging and dates from 1926. These books are often found on Etsy, Ebay and vintage/second hand shops. As a general rule they sell for between $12 and $40.
lovely diary- and unused? is that crocodile leather? absolutely divine.
Not sure if it is snake or alligator/crocodile but it is leather. Never ever been used!