Mark Van Blarcom Slade (born May 1, 1939) is an American actor, artist, and author, particularly remembered for his role of Billy Blue Cannon on the NBC Western television series The High Chaparral.

Slade moved to New York City to attend the American Academy of Dramatic Arts,[2] supporting himself by working at the 21 Club.

In the early 1960s, he moved to the West Coast, where he was cast as Seaman Jimmy "Red" Smith in the feature film Voyage to the Bottom of the Sea (1961).

He appeared only in the first half of the first season because he departed to become a semi-regular, Eddie, in the CBS sitcom Gomer Pyle, U.S.M.C., starring Jim Nabors.

In the 1965–1966 television season, Slade played Radioman Patrick Hollis in the NBC sitcom The Wackiest Ship in the Army.

As an artist, Slade's illustrations, political cartoons, caricatures, and comic strips have run in numerous newspapers, magazines, and prominent publications around the world.

His collaboration with producer/writer Danny Arnold (Barney Miller television series) resulted in the long-running comic strip, "Howard and Friends".

As a writer, Slade is well known for writing and playing the guest role in the "Cliffy" episode of The Rookies television series, which won him critical acclaim and numerous citations.

Published in late 2014, Of Pain and Coffee, a collection of sooth-sayings and soliloquies that explore life's foibles and fears, joys and heartbreaks, with illustrations by the author, was released.

In December, 2014, Mark published a companion book, Someone's Story, that takes the reader on an emotional journey through those brief moments when one can feel another's life.