For decades, students desperate for a summary of Crime and Punishment or a thematic analysis of motherhood in Toni Morrison’s Beloved looked no further than the yellow and black guides available at their local bookstore. Started by a Nebraska bookworm in 1958, CliffsNotes has been the salvation of many a time-crunched, inquisitive—and yes, downright lazy—student. But who was Cliff, anyway? And who wrote the guides? Consider this your study guide.

1. THERE REALLY WAS A CLIFF.

Born in Rising City, Nebraska in 1919, Clifton Hillegass was a voracious reader who reportedly read five books a week up until his death at age 83. A math and physics major in college, he worked as a meteorologist for the Army Air Corps during World War II and eventually took a job distributing textbooks for the Nebraska Book Company. In 1958, he borrowed $4000 from the local bank and began channeling his love of literature into a series of guide books he called Cliff’s Notes. Within 10 years, his little black and yellow books were a million-dollar business. Hillegrass spent 40 years at the helm of his company, retiring after IDG Books Worldwide (publishers of the "For Dummies" series) bought him out for $14.2 million.

2. BEFORE THERE WAS CLIFF'S NOTES, THERE WAS COLE’S NOTES.

In the 1950s, Hillegass got to know a Canadian book store owner and publisher named Jack Cole, who put out a series of study guides called Cole’s Notes. Cole convinced Hillegass to become the U.S. distributor for his guides, starting with a run of 16 Shakespeare titles. Reluctantly, Hillegass agreed, and in 1958 printed 33,000 copies of the guides. With his wife mailing letters to contacts while his daughter stuffed envelopes, Hillegass ran the business out of his Lincoln, Nebraska basement. He sold more than half of the guides, which he renamed, in the first year, and managed to grow his sales each following year. By 1964, Hillegass’s side business had become so lucrative, he quit his job at the Nebraska Book Company and devoted himself full-time to writing and distributing Cliff’s Notes.

3. THE NAME HAS SUBTLY CHANGED OVER THE YEARS.

By the early '60s, Cliff Hillegass was producing so many of his own study guides, he stopped distributing Cole’s Notes. To signify this break, he dropped the apostrophe, and "Cliff’s Notes" became "Cliffs Notes." For decades the company operated under this name, until John Wiley & Sons, which became publisher in 2001, streamlined the name to CliffsNotes.

4. CLIFF NEVER INTENDED THEM TO BE "CHEATER BOOKS."

With their chapter-by-chapter plot summaries, character descriptions, and analysis of structure, themes and other elements, CliffsNotes' literature guides became, for many students, a substitute for doing the actual reading. This dismayed Hillegass, who always maintained that his booklets should be used as supplemental aides. For decades, the company printed an edict alongside Hillegass’s signature inside its guides: "These notes are not a substitute for the text itself or for the classroom discussion of the text, and students who attempt to use them in this way are denying themselves the very education that they are presumably giving their most vital years to achieve."

5. THE COMPANY STILL MAINTAINS THEY ARE STUDY GUIDES.

With plot summaries, pre-written reports and other shortcuts scattered across the internet, the threat of CliffsNotes seems almost quaint these days. Still, the company (now owned by publisher Houghton Mifflin Harcourt) upholds Hillegass’s vision of CliffsNotes as a literary supplement rather than a substitute. "Most people use CliffsNotes by reading a chapter of the book or an act of the play, and then reading the corresponding section in the CliffsNotes," its website asserts, perhaps wishfully.

6. GRAD STUDENTS WROTE A LOT OF THEM.

CliffsNotes has long promoted the fact that teachers and professors write its literary guides. But in interviews, Hillegass revealed that most of the work fell to graduate students. This was primarily a strategic move, since Hillegass didn’t want to overburden his guides with scholarly details and asides. "Someone involved in 20 years of teaching Shakespeare often has too specialized a knowledge," he said in a 1983 interview.

7. SOME TEACHERS USED THEM.

In a 1985 interview with The Chicago Tribune, the executive director of the National Council of Teachers of English admitted some of his members used CliffsNotes. Many of these teachers utilized the guides when they were students, and found them helpful in planning lessons. Others, meanwhile, read the guides in order to catch would-be plagiarists. Writer Jessica Reaves remembered her mother, an English teacher, kept a collection of CliffsNotes at home. "Every time my mom wrote a test or even a quiz on a book she was teaching, she would first sit down with the corresponding Cliffs Notes (and any spinoff cheater books that were on the scene) and painstakingly write the test around the information in the booklets," Reaves wrote in Time magazine. "In other words, she made it virtually impossible to cheat."

8. …BUT MOST TEACHERS HATED THEM.

"The sole purpose of Cliffs Notes is to get a kid through a course and fake it," one teacher told the Tribune. Said another: "What's onerous is not that they summarize the plot, but that they offer commentary on what to think about literature that is accessible and vibrant." In addition to what they considered pre-packaged analysis and summary, teachers have constantly battled with students who plagiarize the guides. Pre-internet, some instructors tried to stay ahead of the problem by assigning books that had no corresponding CliffsNotes. Others took even more drastic measures, like a teacher in Washington, D.C. who told the Tribune he once went into the bookstore next door to his school and moved all the Cliffs Notes copies of Moby-Dick, which he was teaching at the time, to the romance section.

9. THE COMPANY RESPONDED TO CRITICISM BY REVISING ITS GUIDES.

After years of deflecting claims by angry teachers that it was helping students cheat, CliffsNotes in 2000 began updating its literary guides to encourage critical thinking and get students engaging with the source text. The new guides asked questions, referred students to web sources, and offered more background information about each book’s author and the time period in which it was written.

10. SPY MAGAZINE LAUNCHED A PARODY SERIES IN THE LATE '80s.

In 1989, the satirical magazine Spy put out "Spy Notes," a CliffsNotes parody that focused on hip urban novels by authors like Brett Easton Ellis, Jay McInerney, and Jill Eisenstadt. Sample essay questions included "Who’s cooler, McInerney or Ellis?" and "Why do so many authors rely on dead-mother plot devices?" "Spy Notes" got rave reviews from lit critics, but CliffsNotes was not amused. Thinking the booklets too closely resembled its study guides in form—including yellow-and-black covers—and in content, Cliffs Notes sued Spy and won, but had the case overturned on appeal. Summing up the legal intricacies of the case, Spy founder Kurt Anderson told the Chicago Tribune, "We’re not trying to start a competing line of study aids for lazy students."

11. THE PASS/FAIL GRADING REVOLUTION HURT SALES.

Between 1969 and 1975, sales of Cliffs Notes plummeted from 2.8 million per year to less than 1.8 million. The reason? Hillegass and general manager Dick Spellman blamed the rise of experimental grading systems like pass/fail, which swept the nation beginning in the early '70s. "Students weren’t interested in grades anymore," said Spellman in 1983.

12. THEY GOT SHUT OUT OF BARNES & NOBLE.

In 2002, the bookselling chain abruptly took CliffsNotes off its shelves. This wasn’t because the study guides weren’t selling well—quite the contrary. Rather, Barnes & Noble wanted to exclusively stock SparkNotes, a competing study guide series it had purchased the previous year. The guides appeared on shelves for a dollar cheaper than CliffsNotes, giving Barnes & Noble a big sales boost. Eventually, the company lifted the ban, and these days you can find a trove of CliffsNotes titles on its website. 

13. COLLEGE BOOKSTORES BANNED THEM.

Twenty years ago, a group of professors at Villanova University signed a petition asking the school to discontinue sales of CliffsNotes in its campus bookstore. The university complied, and in doing so joined a growing number of schools like Bryn Mawr and Swarthmore in shutting out the popular study guides. Administrators acknowledged it was mostly a symbolic gesture, since students could simply buy the booklets from another source. "We don’t put our institution’s endorsement behind it," the associate dean for academic affairs told the Associated Press at the time. CliffsNotes, meanwhile, wasn’t taking any of this lying down. The company took out a full-page ad in Villanova’s student paper calling the move "censorship."

14. COMPETITION IS FIERCE THESE DAYS.

CliffsNotes has always had competitors. And for decades, the company was able to win out through the strength of its name and through its ties to bookstores, who would typically only sell a limited number of study guide brands. Nowadays, though, with online sources and digital publishers able to bypass traditional channels, the competition has exploded. Looking for a summary of Crime and Punishment? You have hundreds of options to choose from. Even contemporary titles like The Girl on the Train, an unofficial survey by the Observer found, have as many as 10 summary options available through channels like Amazon Kindle and Google Play.

15. THE COMPANY DOESN’T MAKE MUCH OFF ITS LITERATURE GUIDES ANYMORE.

CliffsNotes, like its competitors, has tried to stay relevant with literature guides (all now available online for free) to contemporary classics like All the Pretty Horses, The Kite Runner, and The Poisonwood Bible. But the growth side of the business these days lies with the company’s study guides, test prep guides, and subscription content. Earlier this year, publisher Houghton Harcourt Mifflin announced a subscription service that would offer personalized feedback for students using its test prep and subject learning guides. CliffsNotes's famed literature guides, though, weren’t right for the service, a company rep told Education Week. "We’re not going to write your paper for you," he said.