A breakthrough experience for his generation was the exhibition Founders of Czech Modern Art, organized in 1957 by Jiří Padrta and Miroslav Lamač in Brno.

Here he met artists from the future Confrontation circle as well as generationally related art history students František Šmejkal and Zdenek Felix.

Together with Tomalík, Málek, Sion, Beran, Putta, Barborka, Steklík and others, he belonged to an informal group formed in pubs that called themselves "Somráci" (Vagabonds).

[1] At the end of the 1950s, he took part in a school trip to Leningrad and Moscow; in the deposits of the galleries there, he got to know the originals of the leading figures of the European avant-garde, including works by Picasso, Cézanne, Gauguin, van Gogh, Malevich, Chagall and Kandinsky.

Nešleha's abstract composition for the space of the Music Theatre in Hradec Králové, which he submitted as his diploma thesis, was rejected for ideological reasons and destroyed on the spot; he completed his studies in 1962 with a set of expressive paintings from his junior year, for which he won the school's prize.

Shortly after the August occupation, he married Mahulena Hromádková, a student of art history, and took a study trip with her to Germany, Sweden, Holland and Belgium.

Beginning in 1970 and during normalization, with the help of friends and despite the bans, he participated in international exhibitions devoted to graphic art and drawing, where he won a number of important awards.

Internazionale der Zeichnung, Darmstadt; 9. International Graphic Art Exhibition, Moderna galerija, Ljubljana or Biennale of Drawing in New York, held in 1977.

At the beginning of September 1981, he participated in a private exhibition of eighteen selected artists and theoreticians of modern art at Bedřich Dlouhý's estate in Netvořice, organized on the initiative of Jindřich Chalupecký.

In 1983 he had solo exhibitions of paintings and drawings at the Regional Museum in Kolín (Jan Kříž) and then at the Old Town Hall in Prague (Hana Rousová)[11] and was represented at the prestigious show Dessins tchèques du 20e siècle at the Centre Georges Pompidou.

Subsequently, they invited the composer Jan Klusák (as a theoretician) and the architect Karel Kouba for an upcoming unofficial multimedia exhibition, which was to take place in People's House in Vysočany at the end of 1989.

After the collapse of the communist regime, it was never held and The Backwards were given the opportunity to exhibit in the Nová síň Gallery and in the Mánes Building of the Society of Visual Artists.

[14] In autumn 1989 Pavel Nešleha made a study trip to Italy (Venice, Florence, Rome), where he became more familiar with Caravaggio's and Tintoretto's paintings.

[15] In 1990, Nešleha received a creative grant from The Pollock-Krasner Foundation, and from the same year until 2002 he was the head of the painting studio at the Academy of Arts, Architecture and Design in Prague.

On the occasion of the AICA Congress in Prague, The Backwards installed their individual artefacts, created at the end of the communist regime, in Mánes as a joint work under the title "Pile".

In September 2003, shortly before the opening of his personal exhibition of pastels from the series Records of Light at the Gallery of Modern Art in Roudnice nad Labem, he unexpectedly succumbed to an insidious illness.

At the turn of 1959/1960, he became familiar with the works of Antoni Tàpies, Jean Dubuffet, Alberto Burri and Vladimír Boudník and, like most of his generational contemporaries, he devoted himself to structural abstraction in graphic art and painting (Untitled, mixed media, 1959).

Playing with photographic and later television images brought new themes and transformation to the grotesque presentation of human downfall in response to the trauma of occupation.

Its interior space with a light projection of organic forms of the human body, which contrasted with the geometry of the architecture, was intended to provide the viewer with an opportunity for meditation.

The veristically processed element was at first critically permeated by the ironic grotesqueness and absurdity with which Nešleha reacted to the manipulation and unfreedom of the incipient normalisation, perceived as a "horrible nightmare".

The peculiar, almost surreal subject matter resulted in the late 1970s in a meditative profundity and in a symbolic appreciation of the phenomenon of light (drawing series Time of Open Doors, 1977; paintings Window, 1978; Melioration, 1981, etc.).

Nešleha's imagination and detailed drawings gave everyday and inconspicuous motifs the dimension of general symbols that were a metaphor for Czechoslovak society at the turn of the 1970s and 1980s.

His imagination was enriched by the roots of the Šumava primeval forests, the erosion of sandstone rocks, the statues of Matthias Bernard Braun in Kuks, or the heads and masks of Václav Levý near Liběchov.

In the mid-1980s, the original idea led to the creation of a monumental environment consisting of four monochrome triptychs in the basic scale of Goethe's system, forming an enclosed space 7 m in diameter around the viewer (Elements, 1983–1984).

[27] He was attracted to the idea of depicting the elements as rolling masses as well as the destructive power of fire, the chilling depth of space and the eruptive force of the Earth.

[32] During the 1980s, he began to incorporate the paradox of combining illusory painting with real elements into the conception of his works; he created large-scale objects of doors (the series Illusion in Privacy, 1985–1988),[24] assemblages and pictorial installations (Neither on Earth nor in Heaven, 1989).

He worked on them in drawings (Study of Fire, 1988), paintings (Transformations I and II, 1990), photographs and large-scale digital prints (Elements, 1999; the cycles Braun Reflections and Ojbín from 2000, Natural Structures, 2001).

In the 1990s, he devoted himself to mythical themes addressing the irreversibility of human destiny, as evidenced by his pastels and drawings (Icarus's Fall, 1991–1902; Oedipus, 1992–1993; the series Memoirs of the Earth, 1992; and the paintings Is There a Solitude of Space?

[30] In 1997, he presented large-format photo-objects Via canis in Mánes Gallery - photographs of ordinary covers of public lighting poles, which have acquired a special individuality due to the effects of time and rust.