Born in Pennsylvania in 1958, Keith Haring was one of the most influential artists of the 1980s. And had he not died of AIDS-related complications at the age of 31 in 1990, Haring would probably still be playing an important role in the art world today. His creative drive and sense of social criticism would certainly have found an audience in the Trump era.

His style was built on simple lines and figures, which often were drawn in black and white. Yet Keith Haring's works remain timeless and are already classics. He rarely named his pieces; this drawing, created in 1981, is called "Untitled" ⁠— like so many other of his works. Even after 40 years, there's plenty of room for interpretation here: Who is the recipient of this illumination?

In the first half of the 1980s, much of Haring's work was dedicated to his "Subway Drawings." The New York subway served as his canvas during this time, when he created thousands of drawings. He would draw figures and symbols on small black panels that were actually intended to be used for advertising purposes. But his "stories" were so simple that even the rush hour crowd could relate to them.

Here's another work that bears no title, created in 1982. Haring would often use enamel paint and neon colors on metal. When it came to interpretations, he would rarely comment. To this day, people want to know what he was trying to say. What is this big red figure in the painting? Is it an animal that is taking some kind of revenge on little green humans? Is it juggling or singing to them?

But there also is some repetition among the motifs in Haring's imagery. Soon after the murder of John Lennon in 1980, he started to create drawings of people with holes in their bodies. In this example, Haring combined that motif with religious symbolism, creating a human cross. The death of the Beatles singer had left a strong impression on the artist.

Haring took a clear and strong stand against racism, homophobia and any other form of ignorance. This was especially the case when there was script to complement his motifs. Haring was aware that he, too, had contracted HIV, which at that time was still a fatal disease. He vehemently opposed any silence and repression around AIDS, which was particularly affecting the gay community.

Impressed by ancient Egyptian hieroglyphs, Haring adopted their form of communication by developing characters that were reduced to just a few lines. "There is within all forms a basic structure, an indication of the entire object with a minimum of lines, that becomes a symbol," he said in 1978.

Haring was nothing if not a contemporary artist responding to the pressing issues of the day. With this untitled vinyl painting on tarp, Haring reacted to John Lennon's murder on December 8, 1980. "I woke up the next morning with this image in my head — of the man with a hole in his stomach — and I always associated that image with the death of John Lennon."

Although inspired by graffiti artists, Haring did not consider himself one of them. As his work progressed, he created a signature tag: starting with the outline of an animal, the tag began to resemble a dog; later in his work, it rather appeared as a person crawling on all fours.

Numerous symbols and figures appear repeatedly throughout Haring's work. A simple red heart, signifying love is shown here as a gamble two people take. On the right half of the image is the artist's unique Andy Mouse, a character derived from the Disney figure but tweaked in homage to pop artist Andy Warhol. Context varies, but Andy Mouse is seen as a critique of mass consumerism and pop culture.

Haring was a contemporary of Neil Postman, famous for his book "Amusing Ourselves to Death"; both were ahead of their time as critics of the role of TV and computers in our lives. The screen-headed caterpillar shown in this painting from 1983 combines common symbols in Haring's work to delivers his message of warning that machines pose acute danger to people and could spell the end of humanity.

Adept at critiquing modern culture through symbols he employed, Haring often showed the cross as a place of death or being used by people to commit murder. The cross seen here can be said to represent evangelical Christianity and the trend toward televangelism that swept the US in the early 1980s. In interviews, the artist warned of the danger of dogmatism and "control religions."

Whether you want to interpret the x as the marker of a target or as another letter in the alphabet so frequently used by Haring in his work (and which the exhibition at the Albertina in Vienna is named after), the symbol appears again and again. In this instance, it appears to represent the mob mentality that tears people apart.

Although he died of AIDS at 31, Haring was famous for his politically-driven work even in Europe. He was asked to draw a mural on the Berlin Wall in the late 80s, and painted public service messages, including "Crack is Whack." The turbulence of the 1980s, a decade characterized in the US by the discovery of HIV, military action and the rampant greed of Wall Street, are common themes in his art.

Mixing metaphors, this acrylic painting could be considered an ironic take on the tale of the Golden Calf, here featuring a red monkey worshiped by many. Monkeys are depicted throughout Haring's oeuvre, most remarkably in his work supporting the AIDS advocacy organization ACT UP, which evokes the three wise monkeys from the proverb "hear no evil, see no evil, speak no evil."

Early in his career, Haring sought out opportunities to bring his art to a broader audience — and found it on the empty, black-matted billboards of the early 80s New York subways. Graffiti had already inched into every corner of the city, but Haring took a different approach, using chalk instead of marker to create temporary drawings, similar to this later self-portrait.

Haring used a similar technique to the continuous process employed by Picasso, according to the latter's son, Claude. "He just stayed close, ... painting it from top to bottom — bending on his knees, and never once stepping back to see how it looked. Only after he had covered the entire door did he step back, and that's when the door was finished and became a marvelous painting."