Thumbographs are little books that people in England used, in the early 1900s, to collect thumbprints from friends, from people they admired, and from anyone else whose thumbprints they wanted to collect.
Thumbographs play a role in Austin Freeman’s detective novel The Red Thumb Mark, which introduced the world to Freeman’s fictional detective/physician/lawyer John Thorndyke. Here is a passage from that novel:
“Is the ‘Thumbograph’ in your bag?” interrupted Miss Gibson, in response to this mute appeal.
“Of course it is, my dear Juliet,” replied the elder lady. “You saw me put it in yourself. What an odd girl you are. Did you think I should have taken it out and put it somewhere else? Not that these handbags are really very secure, you know, although I daresay they are safer than pockets, especially now that it is the fashion to have the pocket at the back. Still, I have often thought how easy it would be for a thief or a pickpocket or some other dreadful creature of that kind, don’t you know, to make a snatch and–in fact, the thing has actually happened. Why, I knew a lady–Mrs. Moggridge, you know, Juliet–no, it wasn’t Mrs. Moggridge, that was another affair, it was Mrs.–Mrs.–dear me, how silly of me!–now, what was her name? Can’t you help me, Juliet? You must surely remember the woman. She used to visit a good deal at the Hawley-Johnsons’–I think it was the Hawley-Johnsons’, or else it was those people, you know–”
“Hadn’t you better give Dr. Thorndyke the ‘Thumbograph’?” interrupted Miss Gibson.
The World Rugby Museum has an online exhibition of some of the thumb prints of then-famous rugby players.