Before the story, a practical note: I've assembled the ready-made list of every ingredient you'll need to try this one at home. Onto the tale.
The John Collins is named after John Collins, the head waiter of Limmer's Hotel on Conduit Street in London, the early 1800s. Limmer's was a legendary gentlemen's hotel, and Collins was celebrated for a gin cocktail with lemon, sugar and soda that he served to patrons. The drink was documented in British drinking songs of the 1830s-1840s.
A complicated evolution followed: in the U.S., the cocktail became a Tom Collins when the gin used became the sweet Old Tom Gin, while the original London version with dry gin remained a John Collins. The confusion exploded in 1874 with the famous "Tom Collins Hoax," a gag that spread in New York bars where you had to go find a fictional "Tom Collins" who had allegedly insulted you. The Collins family is one of the pillars of classic bartending.
The best way to honor these historical cocktails is to serve them with the right attention. A complete barman kit on Amazon is the fastest way to get started and make a good impression from day one. And if you want to go deeper and give your house the proper bar vibe, a professional cocktail bar station is the final, definitive touch.