In the pursuit of researches and in the reporting of their results, the individual scientist as well as the community of fellow professionals rely implicitly on the researcher embracing the habit of truthfulness, a main pillar of the ethos of science. Failure to adhere to the twin imperatives of candor and integrity will be adjudged intolerable and, by virtue of science’s self-policing mechanisms, rendered the exception to the rule. Yet both as philosophical concepts and in practice, candor and integrity are (...) complex, difficult to define clearly, and difficult to convey easily to those entering on scientific careers. Therefore it is useful to present operational examples of two major scientists who exemplified devotion to candor and integrity in scientific research. (shrink)