Sherlock Holmes is an exceedingly intelligent private detective who values rational thinking above all else, both in himself and in others. He is well known throughout Europe for his ability to solve difficult cases for clients who want to keep their problems secret. Holmes, in partnership with Watson, has built a reputation for solving seemingly unsolvable crimes, owing to his extraordinary powers of observation and penchant for deductive reasoning. That is, he collects data others may not notice, and then uses that data to draw conclusions. The answer he’s left with is invariably the only logical explanation. Holmes is also a master of disguise, able to completely transform himself so that he can sneak into places and talk to people without being noticed. This skill allows him access to the information he needs to solve his cases.

Holmes's intelligence and determination make him a great detective, but they preclude him from forming close relationships. Few people can operate at Holmes's mental level, which is why Irene Adler is so appealing to him. Since he is a bachelor fully dedicated to his work, Holmes spends most of his time alone in his Baker Street apartment, obsessing over his cases.