Émile Durkheim is listed in every reference book with Max Weber and Karl Marx as a principal founder of modern sociology. Of the three pioneers, Marx was preeminently a politician, secondarily an economist, and his analysis of society per se was usually limited to an almost mechanical passage on class conflict. Suicide is caused, in Durkheim's view, not by a person's tragedy, or his mental breakdown, or his total frustration, but by "social currents". There was a consistency of national statistics over time: the rank of European countries' suicide rates remained almost constant during three periods of the nineteenth century. A crucial problem is that the whole argument of the book rests on the statistics that Durkheim collected from whatever sources he could find, with no mention of how accurate an index they were of what he was examining. Almost all more recent analysts emphasize that official data about suicide are untrustworthy.