In this Lucas Cranach woodcut, Martin Luther and other reformers give Communion to the princes of the House of Saxony. Luther hired Cranach to illustrate his printed works. (National Gallery of Art/image courtesy National Gallery of Art)

Richard Higgins is a writer and editor in Concord, Mass., and the author, most recently, of "Thoreau and the Language of Trees."

Five hundred years after purportedly nailing the world's most famous post to a chapel door in Germany, Martin Luther is being remembered this fall for sparking the revolution that rent and remade Western Christianity. Somewhat lost in its shadow is another transformation the German monk led, one of no less influence on our culture: the print revolution.

An obscure monk, professor of theology and parish priest in backwater Germany in October 1517, Luther became Europe's first best-selling author and first mass-media celebrity. In the process, he lifted the fledgling print industry off the ground and, as much as any other single individual, made the book as we know it today.

Johannes Gutenberg, who invented movable type around 1450, usually gets the credit for that. But Gutenberg gave us only the technology that would make John Grisham possible — a press in which cast metal type pieces could be easily inserted and removed. The print industry after him was plagued by poor quality and dependent on producing long, unreadable tomes in Latin for princes and bishops. Many printers, including Gutenberg himself, went bankrupt.

Luther changed all that. His short, inexpensive, provocative books and pamphlets, written in fiery, witty and earthy German that people could easily understand, were wildly successful. His writings electrified Germany and created the first true mass market for books.

The printing press let Luther bypass Rome's monopoly on knowledge and build popular support before the clerics could lock him up or silence him. "Print allowed the Reformation, essentially, to go viral," said Christopher D. Fletcher, a Medieval historian who helped put together "Religious Change and Print, 1450-1700," an exhibit about Luther currently at the Newberry Library in Chicago.

Luther in three years churned out some 30 cheap pamphlets, 300,000 copies of which were printed, turning Gutenberg's invention into the disruptive social media of its day. In 1520 alone, there were 35 editions of two of his works, "Address to the Christian Nobility of the German Nation" and "The Freedom of a Christian."

Luther was not the first to use pamphlets to incite reform — the friar and political agitator Girolamo Savonarola did so in Florence in the 1490s — but he perfected the new form. These and his immensely popular German translation of the New Testament made him the most published author since the invention of printing, according to Andrew Pettegree, a British Renaissance historian and early-print specialist who documented Luther's impact on books and printing in his own 2015 book, "Brand Luther."

"Printing made Luther who he was," he said in an interview, "but it's also true that Luther made printing into the success it became."

The keys to his success — in addition, of course, to the power of his ideas — were his skill as a writer and his recognition of the importance of the quality and appearance of his books.

Luther had one advantage the Roman cardinals in their silk and ermine capes lacked. His experience teaching, preaching and ministering to his parish in Wittenberg, a provincial town in northeast Germany, had taught him how to speak to people. "He had an instinctive grasp about how to talk to a lay audience," said Pettegree, a history professor at the University of St Andrews in Scotland, who has written widely on the history of communication, especially the impact of early pamphlets and broadsheets.

Luther needed that skill to get Germans to read the Bible themselves. Before translating it, he wandered the streets and markets, sometimes in disguise, "to listen to ordinary Germans" and capture the simplicity and directness of their speech, said David Spadafora, a historian of ideas and president of the Newberry, an independent research library. In his translation, he noted, Luther famously inserted the word "allein," or "alone," into Romans 3:28, making Paul say that one is saved not simply "by faith" but "by faith alone" (thus not by works), a key element of Luther's theology.

And for any readers not persuaded of Rome's errors by the woodcut illustration of the Whore of Babylon in a papal crown, Luther added short notes in the margins to make his points. The final work sold out upon its release in September 1522 and had to be reprinted that December.

Brevity was another virtue Luther practiced in print. At the time, theological works were written in an obtuse dispositional style of Latin in which more was better. "Luther took a huge step into the unknown by writing short works," Pettegree said. His "Sermon on Indulgences and Grace," for example, unlike the verbose discourses of the day, "was a master class in brevity that got straight to the heart of the matter." It was reprinted a dozen times in 1518 alone.

Half of Luther's 45 original works were short sermons that fit into eight pages. This sped up and simplified production because the printer needed to use only a single sheet, or folio, to print an eight-page pamphlet. Cheap, easily portable and highly readable, these works gave ordinary people access to theological ideas that had been the purview of a small elite.

Luther was not the first to use the vernacular in printed works, said William Stoneman, an early-book specialist at Harvard's Houghton Library. But his use of German as he replied to his critics demonstrated that print could be used flexibly in a public debate.

Printing in 1517 was not very good. Books frequently had off-center or irregular lettering and were full of errors. Luther saw this as a limitation, essentially recognizing, four centuries before Marshall McLuhan, that the better the medium, the wider and more effective the message. Despite being a scholastic and having a low opinion of printers, he took an active role in the production of his works, rolling up his sleeves to correct errors and cajole printers to improve their products. He insisted that the type be legible, the lines even and the design elements centered. Eventually he lured a more competent Leipzig printer to open a shop in Wittenberg.

He recruited the famous woodcut artist Lucas Cranach, a friend and wealthy Wittenberg burgher, to improve the appearance of his works. Cranach created exquisite illustrations and simple, elegant designs that were the envy of other printers. His iconic woodcut of the Augustinian monk in a cowl, used on the title pages of his Wittenberg works, made Luther's the most famous face in Christendom. The standard Cranach set immeasurably improved the design of books.

While Pettegree makes a case for Luther's single-handed impact on the book, some scholars are less willing to grant him such a role. "There was a significant boom in printing to meet demand for what Luther had to say, but Luther did not save printing," said Spadafora. "What he did do was to provide a new set of new options, and a new audience for printers, that allowed printing to grow dramatically."

To Pettegree, what made Luther special was his genius for recognizing the potential of a new form of media to speak directly to people and to create a movement that reshaped both the book and German public life — a genius that, in the end, also transformed Western society.

In the 1450s, Gutenberg's press was immediately recognized as a game changer. But it was Luther's success, Pettegree holds, that gave it the game it would change.

To Luther, it was all preordained. He called the printing press a literal gift from God "whereby the business of the Gospel is driven forward." Right onto bestseller lists, then and for centuries to come.