Professor James Moriarty is a fictional character and criminal mastermind created by Sir Arthur Conan Doyle to be a formidable enemy for the author's fictional detective Sherlock Holmes. He was created primarily as a device by which Doyle could kill Holmes and end the hero's stories. Professor Moriarty first appears in the short story "The Adventure of the Final Problem", first published in The Strand Magazine in December 1893. He also plays a role in the final Sherlock Holmes novel The Valley of Fear, but without a direct appearance. Holmes mentions Moriarty in five other stories: "The Adventure of the Empty House", "The Adventure of the Norwood Builder", "The Adventure of the Missing Three-Quarter", "The Adventure of the Illustrious Client", and "His Last Bow".

Moriarty is a criminal mastermind who uses his intelligence and resources to provide criminals with crime strategies and sometimes protection from the law, all in exchange for a fee or a cut of profit. Holmes likens Moriarty to a spider at the center of a web and calls him the "Napoleon of crime", a phrase Doyle lifted from a Scotland Yard inspector referring to Adam Worth, a real-life criminal mastermind and one of the individuals upon whom the character of Moriarty was based. Despite appearing only twice in Doyle's original stories, later adaptations and pastiches have often given Moriarty greater prominence and treated him as Sherlock Holmes' archenemy.
詹姆斯·莫里亚蒂教授是亚瑟·柯南·道尔爵士创造的一个虚构人物和犯罪主谋，是作者虚构侦探夏洛克·福尔摩斯的可怕敌人。他主要是作为道尔杀死福尔摩斯并结束英雄故事的一种手段而创作的。莫里亚蒂教授首次出现在短篇小说《最后问题的冒险》中，该小说于1893年12月首次发表在《斯特兰德杂志》上。他还在福尔摩斯的最后一部小说《恐惧谷》中扮演一个角色，但没有直接露面。福尔摩斯在另外五个故事中提到莫里亚蒂：《空屋历险记》、《诺伍德建筑商历险记》，《失踪的四分之三历险记》和《光辉客户历险记》以及《他最后的弓》。

莫里亚蒂是一名犯罪主谋，他利用自己的情报和资源为罪犯提供犯罪策略，有时还提供法律保护，所有这些都是为了换取费用或利润。福尔摩斯将莫里亚蒂比作网络中心的蜘蛛，并称他为“犯罪的拿破仑”，这是道尔从苏格兰场的一名督察那里借用的一句话，指的是现实生活中的犯罪主谋亚当·沃斯，莫里亚蒂这个角色的原型之一。尽管在道尔的原创故事中只出现过两次，但后来的改编和模仿往往使莫里亚蒂更加突出，并将他视为福尔摩斯的宿敌。
