German physicist and discoverer of X-rays.

In the early part of his career Roentgen built up a solid reputation as a physicist, but it was not until 1895, while he was rector of the University of Wurzburg, that he shot to fame with the discovery of X-rays. For this he was awarded the first Nobel Prize for Physics in 1901. Roentgen was alerted to the new phenomenon when he noticed that some barium platinocyanide crystals near a Crookes tube with which he was experimenting were fluorescing. Hundreds had used this apparatus before, some even observing phenomena such as fogged photographic plates, but all had ignored their observations.

Roentgen spent the next six weeks in intense experimentation with the new rays. Towards the end of the year he took an X-ray photograph of his wife's hand, anticipating the significance of his find for modern medicine.

Roentgen was a reticent, unassuming man, refusing to give the expected lecture on receipt of his Nobel Prize. He continued in academia until he retired (from the University of Munich) in 1920.