1) Steinbeck originally titled his book "Something That Happened" but later changed it after reading a poem by Robert Burns called "To a Mouse". 2) The poem describes a mouse whose nest is destroyed by a plow, much like the farmer feels sorry for disturbing the mouse's home. It includes the line "the best laid schemes o' mice an' men gang aft agley" which Steinbeck used for the title of his novella. 3) The poem suggests that no matter how much work and planning goes into something, things can easily go wrong, just as happened to the mouse's nest. This relates to the themes in Steinbeck's book about the fragility of dreams and plans.