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,
Aufbau principle building-up principle or the aufbau rule. The details of this "building-up" tendency are described mathematically by atomic orbital functions. Electron behavior is elaborated by other principles of atomic physics, such as Hund's rule and the Pauli exclusion principle. Hund's rule asserts that even if multiple orbitals of the same energy are available, electrons fill unoccupied orbitals first, before reusing orbitals occupied by other electrons. But, according to the Pauli exclusion principle, in order for electrons to occupy the same orbital, they must have different spins (−1/2 and 1/2). As we pass from one element to another of next higher atomic