The word "sibilance" refers to pronunciations of the letter "s," including the emission of a hissing or whistling sound. As the title of Sally Van Doren's fourth collection of poetry, the word alerts readers to the sounds of language in the poems that follow in abecedarian order. Filled with wordplay, Van Doren's poems vacillate between the extremes of joy and despair, by turns witty and chagrined, punning and reflective.