Love is that condition in which the happiness of another person is essential to your own. Jealousy is a disease, love is a healthy condition. The immature mind often mistakes one for the other, or assumes that the greater the love, the greater the jealousy.

About Robert A. Heinlein

Robert Anson Heinlein (; July 7, 1907 – May 8, 1988) was an American science fiction author, aeronautical engineer, and naval officer. Sometimes called the "dean of science fiction writers", he was among the first to emphasize scientific accuracy in his fiction, and was thus a pioneer of the subgenre...