"The centerpiece of the film Life of Pi is a boy adrift on a lifeboat with a tiger in the middle of the ocean. That's easy enough for Yann Martel to describe in his novel — but hard to make happen on the set of a movie. As it happens, Pi is in theaters with another movie based on an "unfilmable" novel:Cloud Atlas, with six different plots in six different time periods."

"Some books are challenging to film because they're challenging to read. TakeUlysses, James Joyce's stream-of-consciousness masterpiece, published in 1922."

"'Ulysses was for a very long time considered unfilmable both because of the complexity of the plot and the point of view of the characters,' says Maria Konnikova, a freelance writer who recently explored unfilmable books for The Atlantic."