Several of the particular techniques recommended in these publications subsequently have been used in criminal tampering incidents. The published sources of technical guidance for the would-be tamperer and poisoner are examined in detail to alert forensic scientists, law enforcement authorities, and the food and drug industry to the particular techniques that are being advocated. Possible criminal and civil liability of the publishers and authors is discussed. The author suggests that food and drug retailers consider the wisdom of selling magazines that advertise the availability of revenge, and murder manuals advocating product tampering and poisoning, that food and drug manufacturers test the effects on their products of the contaminants that are being recommended, and that investigators be alert to the existence of such manuals and mail-order suppliers of poisons. (Author abstract)