epigraph

1. N-COUNT An epigraph is a quotation at the beginning of a book or chapter of a book. (卷首或章节前的)格言; 引语[usu N 'to' n]

The epigraph to O'Rourke's book is from de Quincey's Confessions of an English Opium Eater. 奥罗克著作卷首的引语取自德·昆西的《瘾君子自白》。