Just after April Fools’ Day in 1922, Hermann Rorschach, a psychologist who used a collection of symmetrical inkblots to treat patients with manic depression and schizophrenia, died of appendicitis in Herisau, Switzerland, at the age of 37. Had he lived, he would have been 40 when his inkblots made landfall in the United States in 1925; 55 when they emerged as a helpful tool for profiling college applicants; 62 when the Pentagon used them to fashion a line of tropical shorts for World War II veterans; and 99 when Andy Warhol poured paint onto a canvas in 1984, folded it in half, and opened it to reveal his first inkblot-inspired painting. Rorschach would have been 121—unlikely, but not impossible—when Gnarls Barkley released his 2006 music video for “Crazy,” which featured a series of liquefied inkblots that morphed into threatening or reassuring shapes, depending on one’s perspective. And he most certainly would have been dead by 2016, when the film Arrival imagined a world in which aliens could communicate with humans by means of a visual language written in a mysterious, inky pattern.

Over the past century, Rorschach would have seen his inkblots morph from an obscure therapeutic instrument into a nearly universal cultural meme, at once a familiar touchstone for art, music, film, and fashion, and a controversial test for assessing job applicants and prosecuting criminal defendants. Perhaps he would have wondered why his inkblots, once reserved for the assessment of patients with serious mental illnesses, should have emerged as the preeminent metaphor for the relativity of all acts of perception and the flexibility of all personalities. “I am like a Rorschach test,” Barack Obama proclaimed in a 2008 interview. “Even if people find me disappointing ultimately, they might gain something.” “I tell people that Donald Trump is a Rorschach test,” echoed Jared Kushner, Trump’s son-in-law, last year. “People see in him what they want to see.”

Damion Searls traces the long arc of Rorschach’s influence in his scrupulously researched new book, The Inkblots: Hermann Rorschach, His Iconic Test, and the Power of Seeing. Equal parts biography and cultural history, The Inkblots traverses Rorschach’s short and undramatic life in Switzerland, Russia, and Germany, and his inkblots’ far longer and more interesting afterlife in the United States, where they came to play a crucial role in postwar organizational psychology.

It was impossible for Rorschach to know, or even to dream, that his blots would play the outsize role that they did in the modern cultural imagination. When he first attempted to publish the test in 1918, he encountered a staggering series of obstacles: money (the publishers he approached wanted him to pay to reproduce the blots), a wartime paper shortage, and skeptical colleagues. When the blots finally appeared in Rorschach’s book, Psychodiagnostics, in 1921, they were rejected by German academic psychologists as crude and insufficiently theorized. Shortly thereafter, at the height of his professional uncertainty, Rorschach died.

The inkblots would have died with him, were it not for the child psychologist David Mordecai Levy, who, in 1923, translated Psychodiagnostics into English and taught the first U.S. seminar on the Rorschach. Gradually at first, and then with a rapidity that shocked the psychiatric community, Levy’s students and colleagues adopted Rorschach’s inkblots for testing the psyches of patients, college students, artists, army officers, and the “strange and mysterious” people of far-flung African and Asian nations. It was not long before everyone knew, more or less, the Rorschach protocol: A psychologist would quietly pass her subject Rorschach’s inkblots, one at a time; first the five black-and-white cards, then two with large splotches of red, and finally three multicolored ones. “Tell me what you see,” she would say, and wait for an answer.