An absolutely essential book in the philosophy and sociology of science. Originally published in 1935, this truly remarkable book seems to anticipate major arguments and concepts from some of the most prominent figures in the philosophy and sociology of science since the 1970s. Fleck's concepts of thought style and thought collective is suggestive of Kuhn's notion of a paradign and Foucault's episteme; his distinction between vade mecum science and experimental practice seems to anticipate Latour's distinction between ready-made science and science in action.

Perhaps most importantly, Fleck defty and persuasively explains that his radical contextualization of knowledge does not amount to relativism. He is much better than more recent philosophers and sociologists of science at showing that, although facts are not plucked whole from nature like ripe fruit but created and developed by scientists so that what might be a fact in one historical context need not be in another, facts are nonetheless very substantial and real.

Most interestingly and uniquely, Fleck gives makes clear and persuasive an idea that as a historian has always seemed doubtful to me: that an idea could be ahead of (or behind) its time. Surely this is a book that was ahead of its time when it was published in 1935. Rather, it seemed to capture perfectly the key ideas and spirit of science studies as they have developed since the 1970s. ( )