Worldbuilding is the process of constructing an imaginary world, sometimes associated with a whole fictional universe. The term "world-building" was first used in the Edinburgh Review in December 1820 and appeared in A.S. Eddington's Space Time and Gravitation: An Outline of the General Relativity Theory (1920) to describe the thinking out of hypothetical worlds with different physical laws. The term has been used in science fiction and fantasy criticism since appearing in R.A. Lupoff’s Edgar Rice Burroughs: Master of Adventure (1965). The resulting world may be called a constructed world. Developing an imaginary setting with coherent qualities such as a history, geography, and ecology is a key task for many science fiction or fantasy writers. Worldbuilding often involves the creation of m