Holland Cotter puts Piero Manzoni in context:

He was born into an aristocratic family; his full name was Count Meroni Manzoni de Chiosca e Poggiolo. He had an early interest in art but bowing to parental wishes ended up in law school, where he did not thrive. A switch to studying literature and philosophy helped, but not enough to keep him in school. He had prodigious energy. He couldn’t sit still. So around 1955 he turned to making art and taught himself what he needed to know.

The times were right for his adventurous disposition. Cold war Europe was a shifting, uneasy place, traumatized by the past, giddy with new prosperity. Everyone was consuming like mad by day and having nightmares about nuclear bombs at night.

Two different styles of abstract painting reflected the tense atmosphere.

Art informel, the European version of Abstract Expression, was all about that, all about the anguished ego and so on. By contrast geometric abstraction, with roots in Malevich and Mondrian, was about being above it all, about utopia. Manzoni, who was coming to all this from outside the art establishment, had little patience for either position and tried to shake them up.

He made gestural pictures but with gooey tar instead of paint, so they’re not soulful, they’re gross. As for geometric abstraction, he covered canvases with coats of gesso and left them like that, primed, but that’s all. They look blank, as if waiting for a real painter to show up.

He was one of many artists worldwide bent on bumping off art as they’d known it. Lucio Fontana, a hugely influential senior figure, was slashing paintings with knives. Alberto Burri, trained as a doctor, was painting with a blowtorch. In Japan, Yayoi Kusama filled canvases with obsessive dot patterns that left surfaces looking like scar tissue.

Yves Klein, from France, was more hands off. He made production-line art: same-size abstract paintings, all in one brand-name color. And in the United States, as early as 1951, Robert Rauschenberg had done all-white paintings, the only inflections being shadows accidentally cast on the surface.

To Bump Off Art as He Knew It (New York Times)