Reading is fascinating; writing is boring. The act of sitting before a desk and a blank piece of paper or a typewriter or a laptop is about as solitary and unexciting as it gets. But that fact is what makes the “American Masters” (8 p.m., PBS, check local listings) presentation of “Philip Roth Unmasked” so remarkable.

With the exception of a handful of brief clips of fellow writers, critics and old friends, “Unmasked” consists of an extended conversation with the novelist, who sticks pretty much to the subject of his books and his daily routine of writing. Roth, who just turned 80, has received every conceivable literary award, save the Nobel Prize. Since the appearance of “Goodbye, Columbus and Five Short Stories” in the late 1950s, Roth has been a regular fixture of American letters, publishing more than 30 books in the subsequent five decades.

”Unmasked” is intimate without being self-indulgent, and biographical without descending into celebrity or mere gossip. It’s a portrait of a writer just entering his ninth decade discussing his body of work and his failing body, roughly in that order. While more of a monologue than a two-way conversation, “Unmasked” is a rare treat for thoughtful viewers.

Tonight’s other highlights:

• The 2013 NCAA Basketball Tournament (6 p.m., CBS; 7:30 p.m.) continues.

• A nameless foe emerges on “Grimm” (8 p.m., NBC).

• A stubborn proprietor won’t relinquish any control to his daughter on “Kitchen Nightmares” (7 p.m., Fox).

• “Happy Endings” (ABC) returns with two new helpings: the gym faces closure (7 p.m.); Max puts on a false front (7:30 p.m.).

• A coed army battles alien insects in director Paul Verhoeven’s 1997 satire “Starship Troopers” (7 p.m., BBC America), starring Casper Van Dien, Denise Richards, Jake Busey and Neil Patrick Harris.

• Recently discovered texts cast an alternative take on Jesus’ betrayal on “The Gospel of Judas: Revealed” (7 p.m., National Geographic).

• The guys design an aquarium that reflects Las Vegas’ history on “Tanked” (8 p.m., Animal Planet).

• Jake leads Martin to one of Teller’s first patients, a man now awaiting execution, on “Touch” (8 p.m., Fox).