The U.S. holds the largest incarcerated population in the world, and the issues around incarceration are complex and intractable. But art can happen anywhere, as the double meaning in the title “Marking Time” suggests. This major exhibition presents the work of 35 artists. Some are not incarcerated, but address the system in their work. The rest have created their art in prison, working with limited materials and little guidance. The former prisoner Russell Craig, who is quoted in the exhibition book, tells of his first forays into creativity, which he used as a distraction from the reality of prison life. He then began to think he might one day make a living as an artist. He was discouraged by others, but not by his mentor, James Hough, who said, “If you master something, they won’t deny you. . . . Become undeniable.” —E.C.