Spalding Gray’s neuroses-baring monologues take on a different cast in light of his 2004 apparent suicide, but his uniquely queasy humor in Monster in a Box still sneaks up on us with effectiveness. Here, he details his attempts to write the ”solipsistic, narcissistic, self-indulgent pile of poop” that is his 1992 novel Impossible Vacation. The book, with its protagonist/doppelgänger who won’t fly on any airline whose pilots believe in reincarnation, represents Gray’s self-perpetuating need for attention (”Every time I see that I’m being looked at by a celebrity, I’m no longer afraid of death or dying”). Monster — which Gray performed two years earlier on Broadway — starts slowly, and director Nick Broomfield does little to liven it up visually, but by the time Gray lands on his deeply resonant summation (he says of his main character, ”Maybe he should forget about the story and try to take a vacation instead”), it’s hard not to be enthralled. The lack of extras makes sense: The film itself serves as commentary, making-of, and documentary.