The Half-Hearted is a 1900 novel of romance and adventure by the Scottish author John Buchan. It was Buchan's first novel in a modern setting and was written when he was 24 while working for an All-Souls fellowship and reading for the bar.

In Clubland Heroes (1953, revised 1974), Richard Usborne suggested that this novel is in some ways more revealing of the Buchan 'decent-fellow' ethic than any other till the last, Sick Heart River, with Haystoun's death to some extent foreshadowing that of Edward Leithen in the later work. Buchan was only 25 when he completed The Half-Hearted, and had not at that stage quite found his wavelength. But in Haystoun there is much of his later characters Sandy Arbuthnot and Richard Hannay.

David Daniell, writing in 1975, considered the novel to be flawed but interesting. He felt the book weakest in its depiction of London clubs and upper class manners and conversation, but noted other areas that show "flashes of the true Buchan gift". Buchan worked through several of the themes that did not quite succeed in this novel, and returned to them with more assurance in later years, particularly in Mr Standfast (1919), Huntingtower (1922) and John Macnab (1925).

Writing for the John Buchan Society website in 2001, Christine Drews noted that this novel is the one most influenced by John Buchan's study of Greek tragedy. She held that the work's conclusion illumines a path of understanding that can provide perspective on small real-life disappointments and missed satisfactions. The telescoping of the immensity of a single gifted man's death into a purposeful cog in the turning of the wheel of eternity is a foreign, yet broadening philosophy, which shakes the reader's complacency. She concluded that the book is a difficult one to enjoy, but a compelling one to contemplate.

Andrew Lownie, in his 2013 biography The Presbyterian Cavalier, called the novel 'a very uneven book' that reflects Buchan's attempt to reconcile the differing attitudes to life of his Oxford circle: with the 'careless and gay' Lewis Haystoun contrasting with 'the world's iron and salt' represented by the author himself. (wikipedia.org)