Rosalind Franklin’s newfangled “camera” was poised delicately, fifteen millimeters away from the lone, suspended DNA fiber, now chemically stripped of its protein cloak. The experimental device shot a beam of X-rays at its infinitesimal target, which in turn yielded a pattern on some photographic film resting behind it as the radioactive waves diffracted off of the molecule’s atoms and etched a smudgy outline of its shape. The technique, called crystallography, was a bit like making a shadow animal on the wall with one’s hand and a flashlight. Except this shadow image took as long as one hundred hours to create.

Franklin, then just shy of her 32nd birthday and working as a research chemist at King’s College in London, had to rush off to a meeting at the Royal Society and so didn’t wait around for the full image to come into focus. (Raymond Gosling, a young Ph.D. student was there to run the machine in her absence.) But on May 2, 1952, when she returned to her lab to see the crystallographic picture of DNA—the 51st photograph she had taken—the image was beautiful. It “showed a stark x, formed of tigerish black stripes radiating out from the center,” writes Brenda Maddox in her wonderful biography, Rosalind Franklin: The Dark Lady of DNA. “The spaces between the arms of the x were completely blank. It was the clearest picture ever taken of the B form of DNA, unquestionably a helix.”

It was that picture—capturing the helical structure of DNA—that refocused the thinking of James Watson and Francis Crick, who would announce their own discovery of the structure of life’s molecular building block less than two years later.

The way they got to view that crystallographic image—Franklin’s research colleague, Maurice Wilkins, showed it to Watson without Franklin’s knowledge or approval—remains a matter of some controversy, which Anna Ziegler captures in her play, Photograph 51. As for Franklin, who died of ovarian cancer in 1958 at the age of 37, she never quite got her due.

Four years later the Nobel Prize went to Watson, Crick, and Wilkins.

While the Prize itself is awarded only to living people (a fact that spares any blame to the Nobel committee for slighting Franklin), the history of science, say many, has glossed over her central role in the discovery.

One can find a similar pattern in the life and work of Austrian-born physicist Lise Meitner. (Ruth Lewin Sime’s 1996 biography on Meitner, which I read last year, is a classic and very much worth reading.) Meitner’s work in elucidating the process of nuclear fission in 1938 is well accepted by her fellow physicists—but Otto Hahn, who won the 1944 Nobel Prize in Chemistry “for his discovery of the fission of heavy nuclei,” barely acknowledged her contribution. The same, unfortunately, goes for some textbooks.