But you can thank the early American photographer George K. Warren for the yearbook as it exists today. Daguerreotypes and their easily tarnished silver plates lost popularity in the 1860s, and Warren needed a way to keep up his business. He turned to negatives, a process invented in the 1830s by William Henry Fox Talbot that evolved over the years to a point where Warren could print multiple images from one negative. He moved his career in a new direction, taking individual portraits and full class pictures, then selling those images to students who had them all bound into class yearbooks.

When photographs weren’t available, student names were simply printed in a book, sometimes alongside drawings, and classmates would sign in the empty space. In other cases, like one from East St. Louis High School in 1914, the yearbooks would take on the original scrapbook style, full of mementos like pressed leaves.

Signatures in these early yearbooks were often lengthy and mainly focused on friendship and remembrance. Almost everyone in the East St. Louis yearbook, plus several compiled from Archive.org and submissions from Facebook and Twitter users, signed with a rhyming poem of some sort, like “Remember me early, remember me late, remember I am an old schoolmate” or “When the future is present, and the present is past, may the light of our friendship burn bright to the last.” Many a signer wanted to be a link in someone’s chain of friendship or a brick in their chimney of friends.

Faculty signatures were nearly as long as classmate signatures, but with an important difference: Not a single one signed with a personalized message. It was all excerpts from poems or plays, or quotes from philosophers. Then, in the early 1900s, faculty signatures mostly disappeared, only reappearing around the 1960s.

By the 1930s, signatures had begun to shorten in length. Classmates signed their names with brief messages, mostly variations of “best wishes” or “good luck.” Then, around 1935, an anti-signature revolution appeared to take place. Some yearbooks, like that of Philadelphia’s Simon Gratz High School, designated certain pages for faculty and classmate autographs, which they signed in a row with only their signatures. In Chicago and other Midwestern towns, students signed by their photos, leaving no notes or best wishes. This trend lasted until about 1940. There’s no good explanation of why this shift took place, but Depression-era ink shortages might offer a partial rationale. Students of the time could have put thrift over memory.

By 1943, New Jersey’s Bound Brook High School and Chicago’s Gage Park High School yearbooks were full of signatures and notes again, complete with little drawings that covered the pages of both. Including “swell” in your signature was the cool thing to do, a trend that finally started to taper off in the 1970s. If you were anything in high school in the 1940s and ’50s, it was definitely swell—a swell fellow, a swell gal, a swell kid, a swell good-looking kid, a swell little gal, a swell guy, the swellest guy—it was inescapable. The good-luck wishes that had appeared in yearbooks in the early ’30s made a comeback as well, sticking around through the late ’50s in various forms: good luck, best wishes, success to you, loads of luck, best of luck, lots of success. The two often combined, creating the epitome of yearbook signatures of these decades: “Best wishes for lots of luck and success to a swell gal,” someone scribbled in a 1947 yearbook from Mount Horeb High School in Wisconsin.