Several times at the outset, Mr. Rothko makes clear what his book is not about, for readers who might come to it with expectations shaped by “Red” (2010), the Tony Award-winning play, or by the stratospheric market heights reached in recent years for Rothko works. (A painting from 1961 sold at auction in 2012 for almost $87 million, setting a record almost broken this year with the sale of another painting for $82 million.)

Because he was so young when his father died, Mr. Rothko writes: “I have no vast cache of private communications to trawl as I think about the art. And certainly the 6-year-old is in no position to write a kiss-and-tell, so those seeking copious revelations about my father’s personal life will be disappointed.” But after three decades of paying close attention to his father’s work and breaking the Champagne bottle, as he describes it, “over the prow of many a Rothko steamer” in museums around the globe, Mr. Rothko said he felt ready to step forward to try to untangle the public’s thinking about these paintings from thinking about his father’s life, which swerves too often toward myth. “People have this image of an irascible, kind of titanic figure,” he said, of an alpha-male Olympian of the Abstract Expressionist movement, smoking and sparring furiously with history. Because of Rothko’s suicide, in 1970, there are the additional readings of his classic sectional paintings, with their totemic weight and sometimes-glowering palette, as statements of existential darkness and foreboding.