Printed card with photo, the purpose of which, I assume, was to be given out to people upon meeting them.
Stanton Henry King was born in Barbados on 1 May 1867 and died 10 November 1939 in Everett, Massachusetts; his death date was contributed by a reader via the comments section below.
After spending some years at sea in the US Navy, he went to Boston and became director of the Sailors' Haven. He was an author and singer and compiler of sea chanties. His books include "Dog Watches at Sea", 1900, where he describes the life of the common sailor.
In response to the query of a reader, I started a family tree for Stanton Henry King and transcribed some newspaper articles I found about him. Interestingly, he was one of 28 or 29 children; the 27th, from his father's third wife. I'm still looking for his parents' names, but I believe he married twice and had at least three children.
A book he wrote about his early years at sea, Dog Watches at Sea, is available at archive.org.