The book is introduced by a poem. The construction "If ..." invites the reader to make a judgment. It alludes to the treatment of people as Untermenschen (German for "sub-humans"), and to Levi's examination of the degree to which it was possible for a prisoner in Auschwitz to retain his or her humanity. The poem explains the title and sets the theme of the book: humanity in the midst of inhumanity.
The last part of the poem, beginning meditate, explains Levi's purpose in having written it: to record what happened so that later generations will "ponder" (a more literal translation of meditare) the significance of the events he lived through. It also parallels the language of the V'ahavta, the Jewish prayer that commands followers to remember and pass on the teachings of their faith.