If I say Richard Matheson, usually most people wouldn't recognize the name.... never heard of him, sorry pal (even in book stores!).
If I say instead: The Twilight Zone, I Am Legend, The Incredible Shrinking Man, The Outer Limits, Spielberg's "Duel" etc... perhaps more people would agree they have at least heard of these tv and cinema productions. The man behind it all is Richard Matheson.

As a matter of fact I have started to know Richard Matheson through films; I'm one of those who read most of the credits at the end of a film. His name kept popping up in a lot of interesting stuff. I simply had to investigate more... what I found was one of the most unknown and genius sci-fi and terror writer I have ever read, "son" of Ray Bradbury and "father" of Stephen King.

--------------------------The Man And His Stories--------------------------
Richard Matheson is known as American author and screenwriter, typically of fantasy, horror (terror is a better definition), or science fiction. His career started in the early 50's with the short story "Born of Man and Woman", the tale of a monstrous child chained in its parents' cellar, it was told in the first person as the creature's diary. This appeared in a Sci-fi magazine and made Matheson imediately famous. In the next 20 years he produced a great number of short stories in which he frequently blends elements of the science fiction, horror and fantasy genres, making important contributions to the further development of modern horror (and making it hard for critics, even nowadays, to identify exactly what genre he belonged).
He had imediate success also as a screenwriter. Plenty of his stories suited perfectly series like The Twilight Zone (some famous episodes of his were Steel, Nightmare at 20,000 feet, Little Girl Lost), he adapted Edgar Allan Poe's stories for Hammer Films and scripted Steven Spielberg's first feature film, Duel, from his own short story (in which a man driving a car on a remote and lonely road starts being stalked by a large tanker truck and its unseen driver). He even wrote a Star Trek episode back in the days (This episode was the first to fully explore Dr. Spock's lineage and is a favorite among die-hard fans).

In 1973, Matheson earned an Edgar Award from the Mystery Writers of America for his teleplay for The Night Stalker, one of two TV movies written by Matheson that preceded the series Kolchak: The Night Stalker.

His novels include titles such as The Shrinking Man (filmed as The Incredible Shrinking Man), and a science fiction vampire novel, I Am Legend, (filmed as "The Last Man on Earth" with Vincent Price, "The Omega Man", starring Charlton Heston, and, more lately, "I Am Legend" with Will Smith), about the last man alive in a future Los Angeles where a virus has turned everyone else into Vampire-like creatures.
Other Matheson novels turned into notable films include "What Dreams May Come", "Stir of Echoes", "Bid Time Return" (as "Somewhere in Time"), and "Hell House" (as "The Legend of Hell House"), most of them adapted and scripted by Matheson himself. Three of his short stories were filmed together as "Trilogy of Terror", including "Prey" with its famous Zuni warrior doll.

During the 50s he also published a handful of Western stories (later collected in "By the Gun"); and during the 90s he published Western novels such as "Journal of the Gun Years", "The Gunfight", "The Memoirs of Wild Bill Hickok" and "Shadow on the Sun" (doesn't he remind you of Stephen King yet? With his Dark Tower? Well it's not totally coincidental although King will never admit it, keep reading). He has also written a blackly comic locked-room mystery novel, "Now You See It...", and the suspense novels "7 Steps to Midnight" and "Hunted Past Reason".

--------------------------The Unknown Writer and his Legacy--------------------------
If his stories became famous, the man himself remained in the shadow. Many film-makers took inspiration from his stories without even paying credit to the man but plenty of homages are still around (in videogames, tv-series, King's books etc). Like someone else said about him, "it seems the parent is now being treated like the bastard child". Producers of blockbuster movies never admit to have taken inspiration from him, and probably they honestly don't realise it at all because, nowadays, his stories are enbedded into the unconcious. He truly "made" what we define as horror today, thanks to the wide film and tv productions between the 50's and the 70's which subsequently inspired more and more film-makers and writers which everyone has heard of.

He invented a new genre that even nowadays is hard to define, changed the rules of terror and sci-fi stories. Ordinary people became unwilling heroes and are thrown into extraordinary circumstances. Monsters and horrors are not anymore in old haunted houses on a cliff over the ocean but sneak into your ordinary life from ordinary items. A truck that transforms a tranquil road trip into a nightmare, a monster on the wing of the plane that you spot from your window at 20,000 ft trying to sabotage the engines and no one believes you. This sort of terror and sci-fi stories sounds rather ordinary today but when he wrote them, Matheson started a whole new world of ideas for the genre which were previously and stubbornly stuck on clichés belonging to centuries old classic horror authors such as Poe and Lovecraft.

Ray Bradbury calls Matheson, "One of the most important writers of the 20th century".
Stephen King credits Matheson as "the writer who influenced me the most (although he never thanks him enough in my opinion because plenty of his stories are "copied" straight from Matheson's).
Stephen King himself adopted his style (of the horror developing from apparently ordinary and every-day situation) and made it an imediate best-seller material.

--------------------------(Partial) Bibliography------------------------
Near some titles you will find movie adaptation if they were made, at least what I remember. A more detailed list is available on IMDb.com and wikipedia (see links at the end of the review)

Novels

* Someone is Bleeding (1953)
* Fury on Sunday (1953)
* I Am Legend (1954) filmed as The Last Man on Earth, The Omega Man & I Am Legend
* The Shrinking Man (1956); filmed as The Incredible Shrinking Man and subsequently reprinted under that title; also the basis of the film The Incredible Shrinking Woman
* A Stir of Echoes (1958); filmed as Stir of Echoes
* Ride the Nightmare (1959)
* The Beardless Warriors (1960)
* Comedy of Terrors with Elsie Lee (1964); filmed as The Comedy of Terrors
* Hell House (1971); filmed as The Legend of Hell House
* The Night Stalker with Jeff Rice (1972)
* The Night Strangler (1973)
* Bid Time Return (1975); filmed as Somewhere in Time and subsequently reprinted under that title
* What Dreams May Come (1978); filmed as What Dreams May Come
* Earthbound (editorially abridged version published under the pseudonym "Logan Swanson" 1982; restored text published under Matheson's own name 1989)
* Journal of the Gun Years (1992)
* The Gunfight (1993)
* 7 Steps to Midnight (1993)
* Shadow on the Sun (1994)
* Now You See It... (1995)
* The Memoirs of Wild Bill Hickock (1996)
* Passion Play (2000)
* Hunger and Thirst (2000)
* Camp Pleasant (2001)
* Abu and the 7 Marvels (2002)
* Hunted Past Reason (2002)
* Come Fygures, Come Shadowes (2003)
* Woman (2006)

Short stories

* "Born of Man and Woman" (1950)
* "Third from the Sun" (1950); adapted as a Twilight Zone episode (1960)
* "The Waker Dreams" (AKA "When the Waker Sleeps") (1950)
* "Blood Son" (1951)
* "The Thing" (1951)
* "Shipshape Home" (1952)
* "Long Distance Call" (AKA "Sorry, Right Number") (1953)
* "Slaughter House" (1953)
* "Mad House" (1953)
* "The Last Day" (1953)
* "Lazarus II" (1953)
* "Mother by Protest" (AKA "Trespass") (1953)
* "Little Girl Lost" (1953); adapted for the series The Twilight Zone
* "The Traveller" (1954)
* "The Test" (1954)
* "Steel" (1956); adapted for the series The Twilight Zone
* "The Children of Noah" (1957)
* "Lemmings" (1958)
* "Deadline" (1959)
* "The Creeping Terror" (AKA "A Touch of Grapefruit") (1959)
* "No Such Thing as a Vampire" (1959)
* "Crickets" (1960)
* "Day of Reckoning" (AKA "The Faces," "Graveyard Shift") (1960)
* "Prey" (1969) (Later adapted to the Zuni Fetish Doll, in the Trilogy of Terror)
* "Button, Button" (1970); filmed as The Box (2008)
* "Duel" (1971); filmed as Duel (1971)
* "Nightmare at 20,000 Feet" (as The Twilight Zone episode in 1963; as segment four of Twilight Zone: The Movie, 1983; first published in 1984)
* "Two O'Clock Session" (1991)
* "The Doll" (as Twilight Zone episode in 1982, published as story in 1993)
* "Of Death and Thirty Minutes" (1993)

Short story collections

* Born of Man and Woman (1954)
* The Shores of Space (1957)
* Shock! (1961)
* Shock 2 (1964)
* Shock 3 (1966)
* Shock Waves (1970) Published as Shock 4 in the UK (1980)
* Button, Button (1970) being filmed as The Box
* Richard Matheson: Collected Stories (1989)
* By the Gun (1993)
* Nightmare at 20,000 Feet (2000)
* Pride with Richard Christian Matheson (2002)
* Duel (2002)
* Offbeat: Uncollected Stories (2002)
* Darker Places (2004)
* Unrealized Dreams (2004)

--------------------------Conclusion-----------------------

Richard Matheson is pleasant to read, in his stories there are often endings with unsuspected twists and likable characters. Apparently the writer is a family-loving and gentle person and you can often feel it through many of his characters which, although their extraordinary and often horrific experiences, they never step-up to become heroes but they remain human, with their limits and passions. That's what makes you like them even more. Behind all this, the plots are incredible.

Of his productions, what I loved the most were the collection of short stories ("Duel: Terror Stories by Richard Matheson" and "Nightmare at 20,000 Feet: Horror Stories") and the novel "I Am Legend" (much better than any film adaptation they ever produced). The Shrinking Man was very entertaining too although the ending was a bit disappointing.

It's a crying shame that his name is generally unknown because it makes it even harder to find his books. You never find them in small libraries or book stores, in big book store chains you often have to order them. Amazon on the contrary has plenty but now, after the latest "I Am Legend" adaptation I suspect he will become, although shortly, a bit more famous and available on the shelves.

I hope I inspired some of you to look for his books. He's really a great writer who deserves much more attention.

I leave you some links about the man himself
http://en.wikipedia.org/wiki/Richard_Matheson
http://www.imdb.com /name/nm0558577/