[10] In 1939, his last year of high school, Lichtenstein enrolled in summer classes at the Art Students League of New York, where he worked under the tutelage of Reginald Marsh.

[11] Lichtenstein then left New York to study at Ohio State University, which offered studio courses and a degree in fine arts.

[13] Lichtenstein entered the graduate program at Ohio State and was hired as an art instructor, a post he held on and off for the next ten years.

Around this time, he began to incorporate hidden images of cartoon characters such as Mickey Mouse and Bugs Bunny into his abstract works.

[10] Lichtenstein's first work to feature the large-scale use of hard-edged figures and Ben-Day dots was Look Mickey (1961, National Gallery of Art, Washington, D.C.).

[18] This piece came from a challenge from one of his sons, who pointed to a Mickey Mouse comic book and said; "I bet you can't paint as good as that, eh, Dad?

[23] Lichtenstein used oil and Magna (early acrylic) paint in his best known works, such as Drowning Girl (1963), which was appropriated from the lead story in DC Comics' Secret Hearts No.

In 1968, the Darmstadt entrepreneur Karl Ströher acquired several major works by Lichtenstein, such as Nurse (1964), Compositions I (1964), We rose up slowly (1964) and Yellow and Green Brushstrokes (1966).

He then applied a glaze to create the same sort of graphic motifs that he used in his paintings; the application of black lines and Ben-Day dots to three-dimensional objects resulted in a flattening of the form.

"[39] Eddie Campbell blogged that "Lichtenstein took a tiny picture, smaller than the palm of the hand, printed in four color inks on newsprint and blew it up to the conventional size at which 'art' is made and exhibited and finished it in paint on canvas.

[42][43] In an interview for a BBC Four documentary in 2013, Alastair Sooke asked the comic book artist Dave Gibbons if he considered Lichtenstein a plagiarist.

Using his characteristic Ben-Day dots and geometric shapes and lines, he rendered incongruous, challenging images out of familiar architectural structures, patterns borrowed from Art Déco and other subtly evocative, often sequential, motifs.

[51] Although Lichtenstein had planned to produce 15 short films, the three-screen installation – made with New York-based independent filmmaker Joel Freedman – turned out to be the artist's only venture into the medium.

[52] Also in 1970, Lichtenstein purchased a former carriage house in Southampton, Long Island, built a studio on the property, and spent the rest of the 1970s in relative seclusion.

A notable example being Artist's Studio, Look Mickey (1973, Walker Art Center, Minneapolis) which incorporates five other previous works, fitted into the scene.

[2] During a trip to Los Angeles in 1978, Lichtenstein was fascinated by lawyer Robert Rifkind's collection of German Expressionist prints and illustrated books.

The White Tree (1980) evokes lyric Der Blaue Reiter landscapes, while Dr. Waldmann (1980) recalls Otto Dix's Dr. Mayer-Hermann (1926).

Small colored-pencil drawings were used as templates for woodcuts, a medium favored by Emil Nolde and Max Pechstein, as well as Dix and Ernst Ludwig Kirchner.

[55] Also in the late 1970s, Lichtenstein's style was replaced with more surreal works such as Pow Wow (1979, Ludwig Forum für Internationale Kunst, Aachen).

[58] Lichtenstein's Still Life paintings, sculptures and drawings, which span from 1972 through the early 1980s, cover a variety of motifs and themes, including the most traditional such as fruit, flowers, and vases.

[62] Interiors (1991–1992) is a series of works depicting banal domestic environments inspired by furniture ads the artist found in telephone books or on billboards.

[63] Having garnered inspiration from the monochromatic prints of Edgar Degas featured in a 1994 exhibition at the Metropolitan Museum of Art in New York, the motifs of his Landscapes in the Chinese Style series are formed with simulated Ben-Day dots and block contours, rendered in hard, vivid color, with all traces of the hand removed.

[65] In 1969, Lichtenstein was commissioned by Gunter Sachs to create Composition and Leda and the Swan, for the collector's Pop Art bedroom suite at the Palace Hotel in St. Moritz.

In the late 1970s and during the 1980s, Lichtenstein received major commissions for works in public places: the sculptures Lamp (1978) in St. Mary's, Georgia; Mermaid (1979) in Miami Beach; the 26 feet tall Brushstrokes in Flight (1984, moved in 1998) at John Glenn Columbus International Airport; the five-storey high Mural with Blue Brushstroke (1984–85) at the Equitable Center, New York; and El Cap de Barcelona (1992) in Barcelona.

[78] Among many other works of art lost in the World Trade Center attacks on September 11, 2001, a painting from Lichtenstein's The Entablature Series was destroyed in the subsequent fire.

In 1996 the National Gallery of Art in Washington, D.C. became the largest single repository of the artist's work when Lichtenstein donated 154 prints and two books.

Outside the United States and Europe, the National Gallery of Australia's Kenneth Tyler Collection has extensive holdings of Lichtenstein's prints, numbering over 300 works.

[87] In late 2006, the foundation sent out a holiday card featuring a picture of Electric Cord (1961), a painting that had been missing since 1970 after being sent out to art restorer Daniel Goldreyer by the Leo Castelli Gallery.

In 2006, the Roy Lichtenstein Foundation published an image of the painting on its holiday greeting card and asked the art community to help find it.

[106] In 2013, the painting Woman with Flowered Hat set another record at $56.1 million as it was purchased by British jeweller Laurence Graff from American investor Ronald O.