C. Northcote Parkinson and journalist Ann Fry (1921–1983), with whom he had two sons and a daughter. In 1958, while still in Singapore, he published his most famous work, "Parkinson's Law", which expanded upon a humorous article that he had published in the "Economist" magazine in November 1955, satirising government bureaucracies. The 120-page book of short studies, published in the United States and then in Britain, was illustrated by Osbert Lancaster and became an instant best seller. It explained the inevitability of bureaucratic expansion, arguing that 'work expands to fill the time available for its completion'. Typical of his satire and cynical humour,
Maupertuis's principle applied the principle only to light, not matter (see ). He arrived at the principle by considering Snell's law for the refraction of light, which Fermat had explained by Fermat's principle, that light follows the path of shortest "time", not distance. This troubled Maupertuis, since he felt that time and distance should be on an equal footing: "why should light prefer the path of shortest time over that of distance?" Accordingly, Maupertuis asserts with no further justification the principle of least action as equivalent but more fundamental than Fermat's principle, and uses it to derive Snell's law. Maupertuis specifically states