Harding's Luck. by E. Nesbit

Harding's Luck, published in 1909, is the sequel to The House of Arden by E. Nesbit. Rather darker and more serious in tone than the previous book, this novel is set in England's Edwardian era, when there was no government-supported welfare and the poor still sometimes starved to death. It centers on young Dickie Harding, a poor, lame orphan boy who is enticed to run away with a disreputable tramp, Mr.
Beale. Beale intends to use him to help carry out burglaries (a plot device not dissimilar to that of Oliver Twist). Nevertheless Beale becomes a substitute father-figure to Dickie and a strong mutual affection develops. The story then introduces a magical device which sends Dickie back in time to the early reign of King James I, where he inhabits the body of the son of the lord of a castle. Despite this new, very comfortable existence, where he is a member of a rich, respected family and no longer lame, Dickie selflessly forces himself to return to his present day because of a promise he had made to Beale and a desire to help Beale lead a more honest life.
Nesbit was a member of the socially-progressive Fabian Society and a friend of H. G. Wells, and it shows in her stories. While Harding's Luck is primarily a children's novel, it touches on many deeper themes and comments seriously on the social conditions of the author's time.