Mortality and Immortality
MacLeish, as indicated by his use of the word "forever," is concerned with mortality and immortality in this poem. Presumably referring to "the page" of one who writes, MacLeish explores how creations, in the poetic sense, and metaphorically, in the ontological sense, can easily be forgotten.
Legacy
In this poem, MacLeish asks what it means to deeply desire that one be revered and remembered—leaving a legacy for future generations. Alongside this question is the question of how to honor that the individual exists and has existed, even after one fades from the collective consciousness.
