Rosalind Franklin

The X-ray diffraction images that proved crucial to working out the structure of DNA are the reason most people arrive at her name. She was a chemist and crystallographer, born in London in 1920, and the images stand now as a kind of shorthand for what she did — though they were the product of a long apprenticeship in exacting method rather than a single stroke of luck.

Her early work was marked by a willingness to test inherited assumptions and to restate difficult problems in forms that could actually be attacked. Correspondence, travel and steady reading built the technical range; collaborations built a working ethos. What distinguished the first results was not novelty so much as clarity, and clarity became a principle she held to. She combined patience with fine detail and a feel for the larger structure of a field, alternating between analysis and construction, experiment and theory.

In mid-career she consolidated technique while widening the range of questions she took on. Rivals and critics sharpened rather than deflected the work; publications and demonstrations turned tentative findings into settled statements. Even the experiments that failed served as tests that improved what came next. She died in 1958, at thirty-seven. The archives that survive show the drafts and corrections alongside the finished prose — the contingency as well as the rigour. Institutions have memorialised the achievement, and successive generations have reread it with new tools, but the more useful inheritance is the method itself, still practised in laboratories and taught in classrooms.