The Protura were discovered relatively late in the history of entomology. The first description of these minute soil arthropods was given in 1907 by the Italian entomologist Filippo Silvestri, who named them ‘Protura’. Shortly thereafter his fellow countryman Antonio Berlese published two brief notes on these animals before his grand monograph of the ‘Myrientomata’, as he named them, appeared in 1909. The centennial of the discovery of Protura offers the opportunity to review our knowledge about these peculiar animals. In the end, we must confess that proturans continue to retain an amazing number of secrets, including basic facts of knowledge about their biology and ecology. Up to the present, they have concealed from scientific observation their sexual life and the mode of sperm transmission. For a long time, their egg deposition and early development were completely obscure topics; only recently has it become possible to conduct first observations on their embryology. The list of open questions can be easily extended: we know only little about their nutritional biology, and next to nothing about their sensory systems, communication, physiological and ecological capacities. The greatest progress in proturan research over the past 100 years has been made in the field of taxonomy. Nonetheless, the road of taxonomy was bumpy and the proturans proved to be awkward travel companions. Species are exceedingly difficult to determine; and the number of living scientists that are able to unambiguously identify specimens at the species level can be counted on two hands. Proturans inhabit soils in all terrestrial regions of the earth (excepting the Arctic and Antarctic regions). Presently, a total of 787 valid species has been described. Because of the high standards of Berlese’s 1909 monograph, several decades would pass before morphological and anatomical research could equal or go beyond his classical landmark. In more recent times, remarkable contributions have been made to the ultrastructural investigation of internal organs and sperm morphology; hereby, the proturans proved again to be odd and unusual in many respects. The peculiarities of Protura have evoked heated debates about their phylogenetic position from the beginning, and such discussions have recently been revived by the introduction of molecular data. The review comprehends an extensive reference list on all research topics except taxonomy, which recently was compiled by Szeptycki (2007).