When one of the funniest people in America writes a book, it's cause for celebration.

That person is Paul Rudnick, whose novels include laugh-out-loud "I'll Take It." He also has written for movies ("In and Out," "Sister Act") and stage ("Jeffrey") and his @PaulRudnickNY Twitter handle is a devastating takedown of Conservatism, 140 characters at a time.

Rudnick's lightly autobiographical "Farrell Covington and the Limits of Style" — comic, but with a fair amount of tragedy — follows Nate from Yale University (like Rudnick) to the present. Working-class theater student Nate falls for wealthy Farrell and remains in love with him — despite family-engineered separations, the AIDS epidemic and bigotry — for five decades.

"Farrell" is more tied to realism than Rudnick's other novels ("I'll Take It" is about a gay man whose fall color trip with his mom and aunts turns into an L.L. Bean outlet store heist), which balances the abundant humor. For instance, when Nate meets Farrell for the first time, he claims his "voice was maddeningly but somehow naturally affected, as if the person had been raised by a bottle of good whiskey and a crystal chandelier."

Things bog down toward the end but, like Curtis Sittenfeld's "Romantic Comedy," "Farrell" deconstructs rom-coms while embracing their many pleasures.

'Farrell Covington and the Limits of Style'

By: Paul Rudnick.

Publisher: Atria Books, 368 pages, $28.99.