Nicholson Baker likes to get to the bottom of things. His first novel, 1988’s “The Mezzanine,” followed every passing thought in the mind of a narrator riding up an escalator. He obsessed over the notion of World War II being a “good war” in 2008’s “Human Smoke”; 2001’s “Double Fold” was a fussy investigation of library preservation protocols. He once wrote a 150-page essay on the word “lumber.”

So writing “Baseless,” his book about the Freedom of Information Act, was only ever going to be an exercise in frustration. He may wish to get to the bottom of things, but FOIA, especially when it comes to matters of national security, will barely let you see where the bottom might be. Any investigative reporter will tell you that FOIA — a law enacted in 1967 that requires the federal government to release records upon request — can often obscure as much as it reveals, thanks to redactions and outright that’s-classified denials. Disappointment is constant regardless of what a journalist is fishing for, and in “Baseless,” Baker is trying to land a whopper: Did the United States use biological weapons on China and Korea during World War II and the Korean War?