In the 1920s, large numbers of black people moved from the agricultural areas of the United Staes, primarily in the south, to the cities of the north, particularly New York. Many settled in Harlem, giving rise to the Harlem Renaissance, in which Langston Hughes played a central role.

This poem does not mention Harlem except in the title. It is, like many Hughes poems, a meditation on the power of dreams; this power is not necessarily benign. Dreams which do not come true, according to the poem, do not always die, either. What might happen to them? Hughes suggests a variety of ways in which they they might shrivel, fester, or spoil like food gone bad. They might merely weigh down the dreamer, or...they might explode.

This is the last line of the poem, generally printed alone and in italics. Its rhyme with the previous line renders it even more striking and forceful. At a time when black people were amassing in the cities in ever greater numbers—educated, talented, ambitious, and frustrated—this poem comes as a clear warning. So far, the mounting frustration of America's black urban population has only soured their own lives, but as the pressure mounts, an explosion seems ever more probable.