On the morning of April 29, 1986, a fire alarm sounded in the Los Angeles Public Library. As the moments passed, the patrons and staff who had been cleared out of the building realized this was not the usual false alarm. The fire was disastrous: It reached 2,000 degrees and burned for more than seven hours. By the time it was extinguished, it had consumed 400,000 books and damaged 700,000 more. Investigators descended on the scene, but over 30 years later, the mystery remains: Did someone purposefully set fire to the library --- and if so, who? Award-winning journalist Susan Orlean investigates this legendary fire to showcase the larger, crucial role that libraries play in our lives.