Dirk Gently is a fictional character created by Douglas Adams and featured in the books Dirk Gently's Holistic Detective Agency and The Long Dark Teatime of the Soul. Adams was working on a third Gently novel, The Salmon of Doubt, at the time of his death.

Dirk bills himself as a "holistic detective" who makes use of "the fundamental interconnectedness of all things" to solve the whole crime, and find the whole person. In fact he is a con man, and the "holistic detective" label is basically an excuse to run up large expense accounts and then claim that every item was, due to the fundamental interconnectedness of all things, actually a vital part of the investigation. (Challenged on this point in the first novel, he claims that he cannot in fairness be considered to have ripped anybody off, because none of his clients have paid him yet.)

Dirk's career as a confidence trickster has been dogged by persistent bad luck: whatever bizarrely improbable thing he claims in order to get money always turns out to be true (or at least appears, by some improbable coincidence, to have turned out to be true), invariably in a way that means that he does not get the money, and often in a way that means he gets arrested, loses his house, or is otherwise severely inconvenienced. Similarly, his various attempts to make money as a fake psychic have resulted in a perfect success rate that leads to awkward questions being asked.

Dirk Gently is actually not this character's "real" name; it is presented early on in the first book that it is a pseudonym for the much less memorable "Svlad Cjelli." "to dirk" is an archaic synonym for "to stab", so essentially "Dirk Gently" literally means "stab gently". A dirk is a type of knife.