The four ghosts who appear in "A Christmas Carol" by Charles Dickens are Jacob Marley, the Ghost of Christmas Past, the Ghost of Christmas Present and the Ghost of Christmas Yet to Come. All four visit Ebenezer Scrooge within the span of a few hours.
Jacob Marley is Scrooge's late business partner who in life was miserly like Scrooge. His ghost appears to Scrooge on the night of Christmas Eve to tell him of three visitors he will soon encounter.
The second ghost to appear is the Ghost of Christmas Past, who comes to remind Scrooge of his childhood. The Ghost of Christmas Present visits next to show him the holiday season in the homes of people with whom he is now associated. Scrooge learns from him that Tiny Tim will soon die if conditions for his family do not change. The Ghost of Christmas Yet to Come shows Scrooge his own grave.