Louis Michel Eilshemius (February 4, 1864 - December 29, 1941) was an American painter, primarily of landscapes and nudes. Although he was academically trained, much of his work has the unself-aware character of naive art.

Born near Newark, New Jersey into a wealthy family, his earliest education was in Europe, after which he spent two years at Cornell University before his art studies began at the Art Students League in New York. He subsequently studied under Bouguereau at the Académie Julian in Paris, and traveled widely in Europe, Africa and the South Seas, returning to the family brownstone in New York City where he was to live for the rest of his life.

His early landscapes show the influence of the Barbizon school and of Corot, and also of George Inness and Albert Pinkham Ryder. It is Ryder whose work is especially recalled by the powerful rhythms of Eilshemius's paintings, rhythms the artist often reinforced by painting sinuous "frames" onto his pictures. His paintings of New York rooftops are as lyrical as his pastoral scenes.

He achieved little public recognition. His later, visionary works depicting moonlit landscapes populated with voluptuous nymphs caused his contemporaries particular consternation, due to their crudely rendered and often extravagantly smiling nudes. These are shown frolicking in forests or waterfalls, either alone or in groups, sometimes defying gravity by floating through the air.

Eilshemius also wrote verse and prose, composed music, painted, philosophized and became notorious for his many eccentric, often vitriolic, letters-to-the-editor of various New York City publications. His lack of public acclaim led him to desperate measures; thinking that perhaps the length of his name was an obstacle to success, he tried signing his paintings "Elshemus". On letterheads and in hyperbolic, self-published flyers he would proclaim his accomplishments: "Educator, Ex-actor, Amateur All-around Doctor, Mesmerist-Prophet and Mystic, Reader of Hands and Faces, Linguist of 5 languages", as well as world-class athlete and marksman, "Spirit-Painter Supreme", and musician whose improvisations rivalled the compositions of Chopin. All of this only reinforced the impression, already suggested by the peculiar imagery in many of his paintings, that he was either mad or a charlatan.

He was not without supporters, however. He was championed by Marcel Duchamp, who "discovered" Eilshemius in 1917 and invited him to exhibit with him in Paris that year. His work was generally well received by French viewers and critics; his admirers included Matisse. Duchamp subsequently helped to arrange Eilshemius's first solo exhibition in 1920, at the Societe Anonyme in New York City. The hostile critical reception to this exhibition, however, finally drove him to give up painting entirely in 1921, although there is a single known painting dated 1937.

Injured in an automobile accident in 1932, he became increasingly reclusive. His health in decline and his family fortune spent, he died in 1941.

Since his death, Eilshemius's work has found a wider audience. One of the artist's few consistent patrons, Roy Neuberger, donated a large body of Eilshemius' work to the Neuberger Museum of Art located at SUNY Purchase College in New York State. Further information about this individual or organization may be available in the Special Collections Research Center Wiki: .