regularities of nature can be captured by simple mathematical relationships is a long way from Blair's (1976, p. 81) notion that "numbers, quite distinct from their empirical use, become a language, as full of metaphor and dimension as poetry". However, before sneering at the idea that numbers in themselves can have a significance, we should remember that the long-standing, and still influential, Platonic tradition within science views numbers as having their own objective existence, and indeed that the physical universe and everything in it is, at root, a mathematical structure made of numbers (see Tegmark [2014] for a recent and accessible account of this position).As well as numbers per se, numerology is often also taken, usually critically, to mean an enthusiasm for simple numerical formulae, usually involving integers, capturing some significant aspect of reality. These have been seen in both the sciences and the social sciences: notoriously, the British physicist and astronomer Sir Arthur Eddington spent many years seeking simple integer relationships as the clue to the universe (Kilmister, 2005). It is clear that there are strong relations between numbers, the physical world and cultural issues, as is clearly shown by the sequence of "kissing numbers," the number of spheres which in any space exactly bound a further identical sphere (Weisstein, n.d.); two points on a one dimensional line bound a third point, six circles circumscribe a seventh, and twelve balls circumscribe a thirteenth. The resultant sequence-three, seven, thirteen-captures the principle significant/lucky/unlucky numbers in numerous cultures, and is numerologically present in the 'leader with twelve followers' meme of Christ, Osiris, King Arthur, and others (Blair, 1976). 4 Therefore, despite the dangers of slipping into a facile numerology, simple numbers and integer relations may still be worth investigating, in science, in the social sciences, and specifically in LIS.There are, in fact, relatively few such simple numbers and number relations in our discipline and what there are have come in from adjacent disciplines. We will consider seven, a suitably magic number in itself, of these. In truth, they are not all very simple: one is very large, some have alternatives, one is a sequence, and one is infinite. These numbers encapsulate a variety of issues: how much information there, or could be; the optimal size of communicating groups; the structure of information networks; the distribution of information activities; and the 4 It would have been nice if the four-dimensional kissing number, which was not known until 2003 (Pfender & Ziegler, 2004) and cannot be intuitively grasped like the small dimension equivalents, had also related to some culturally significant number. Disappointingly, it was shown to be 24, and 25 does not appear to have significance in any culture.