In which Charles Dickens novel does the character of Sydney Carton appear?

Sydney Carton is a central character in Charles Dickens' novel A Tale of Two Cities. He is a shrewd young Englishman and sometime junior to his fellow barrister C.J. Stryver. Carton is portrayed as a drunkard, depressed and self-loathing because of his wasted life. He feels a deep unrequited love for Lucie Manette.

Sydney Carton is introduced into the novel A Tale of Two Cities as a young, sloppy, but brilliant lawyer who bears an uncanny likeness to Charles Darnay (whose original name is Charles Evrémonde), the prisoner he is defending. He uses his great skill to save Darnay from death, passing his case to his colleague Stryver, who takes all the glory for saving Darnay. It is then revealed that Carton both likes and hates Darnay, as he sees him as everything he should be but is not. Carton is called a "jackal" because it appears that, while Mr. Stryver very deftly presents each case, it is Carton's legal acumen that helps win them, though Stryver gets all the credit (a reference to how the jackals help lions with kills, while the lions take all the glory). It is also seen that Carton is an alcoholic who faces a great lack of self-confidence and a great bounty of self-hatred. He develops an unrequited love for Lucie Manette, which he tells her about. He says that he would do anything for her or for anybody she loves.