Read the essays gathered in “Dear Friend, From My Life I Write to You in Your Life” and you’ll be left with the sense that they’re the product of a singular mind, one that has no time for cliches or pandering. For someone who’s devoted so many working hours to literature — there have been two novels and two story collections, each of them admiringly reviewed — she has some notably counterintuitive opinions about art and language and inspiration. Li, who was awarded a MacArthur Fellowship genius grant in 2010, is unlikely to be featured in an anthology of motivational quotes about the writing life; there’s a distinctly dark tenor to her work. Li worked on this book for two years, she says, as long as the period that led to it, a year of descending into the darkest despair and a year of being confined by that despair. The bleakness, which can be summarized with a few generic words — suicide attempts and hospitalizations — was so absolute that it sheds little light on things. Afterward, in an effort to discourage political dissent, she and many other university students were forced to serve a year in the army. For a long time, she worked all day in labs and wrote all night, often keeping at it until 4 a.m.