Probably the most important years in anyone's life are those eight or ten preceding the twenty-first birthday. During these years Heredity, one of the two great developmental factors, bears its crop, and the seeds sown before birth and during childhood come to maturity. During these years also the other great developmental force known as Environment has full play, the still plastic nature is moulded by circumstances, and the influence of these two forces is seen in the manner of individual that results.

Alice Muriel Williamson was an American-British novelist. She was born in America, the daughter of Mark Livingston of Poughkeepsie. She came to England when young. In 1894, soon after arrival in England, she married the magazine editor Charles Norris Williamson (1859-1920), "the first editor to whom she presented an introduction." Many of her books were jointly written with her husband. After her marriage she introduced herself as Mrs. C. N. Williamson. A number of their novels cover the early days of motoring and can also be read as travelogues. Alice apparently said of her husband "Charlie Williamson could do anything in the world except write stories" she said of herself "I can't do anything else." She continued to write after her husband's death in 1920.

Ferdinand August Bebel was a German socialist politician, writer, and orator. He is best remembered as one of the founders of the Social Democratic Workers' Party of Germany in 1869, which in 1875 merged with the General German Workers' Association into the Socialist Workers' Party of Germany.

Paul-Henri Thiry, Baron d'Holbach, was a French-German author, philosopher, encyclopedist and prominent figure in the French Enlightenment. He was born Paul Heinrich Dietrich in Edesheim, near Landau in the Rhenish Palatinate, but lived and worked mainly in Paris, where he kept a salon.