Thomas Harman, a Kent JP, lived at Crayford near Dartford, close to London. For health reasons he was forced to live at home. There he interviewed many travellers passing his house. It was out of those enquiries that he wrote one of the earliest and most authoritative of the so-called cony-catching pamphlets. (A “cony” in common parlance was a rabbit, but in canting language, i.e. criminal argot, a victim.) The Caveat consists of a Preface and Epistle to the Reader followed by 23 descriptions of various categories of vagabond. To this is attached a list of vagabonds known to him, a glossary of canting language, and a fictional dialogue in the canting language. Spelling, punctuation and paragraphing have been modernized.