Every year, the Nobel Foundation in Stockholm, Sweden, announces up to three winners each in the scientific disciplines of chemistry, physics, and physiology or medicine. As of this morning, since 1901, 780 individuals have joined the hallowed ranks of Nobel laureates in these and other categories. And every year, there are murmurings—some louder than others—about the Nobel-worthy scientists who were overlooked. In 1974, when Jocelyn Bell Burnell was left out of the physics prize, her fellow astronomer and Nobel reject, Fred Hoyle, told reporters it was a "scientific scandal of major proportions." Physician-inventor Raymond Damadian famously took out full-page newspaper ads protesting his omission from the 2003 Nobel for MRI technology. This year, some will be asking questions about Robert Gallo, who did not share today's Nobel for medicine or physiology with Luc Montagnier and Francoise Barre-Sinoussi.

Nobel committee proceedings are notoriously shrouded in secrecy, so it's impossible to know all the details behind how each prizewinner is chosen, especially the more recent ones. But, according to Nobel historians, most award exclusions seem to relate to one or more of these criteria: limited slots available (Nobel rules limit the number of recipients to three for each category); ambiguity over who made the crucial contribution; and lack of experience and/or reputation within one's research community.

As we enter the 2008 Nobel season, there are sure to be other alleged snubs. Needless to say, the noble Nobel process is inherently subjective. Still, going through Nobel history, there are a few cases that stand out.

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