Nicholson Baker has already mastered one kind of art, writing books. His novels “The Mezzanine” (1988), “Room Temperature” (1990) and “A Box of Matches” (2003) showcase his gift for finding the extraordinary in the minutiae of everyday life — buying shoelaces, feeding a baby, lighting a match. His 1992 novel, “Vox,” explored more carnal activities and became, famously, a gift from Monica Lewinsky to Bill Clinton. In nonfiction books such as “Double Fold: Libraries and the Assault on Paper” (2001) and “Substitute” (2016), Baker immersed himself in his subjects — for the latter, he spent 28 days working as a substitute teacher in Maine, where he lives. It was an exhausting experience but not as taxing as his next book, “Baseless” (2020), in which he delved into boxes of documents about U.S. military operations in the Korean War.