The authors provide a polygraph primer for police psychologists involved in law enforcement personnel selection. Law-enforcement pre-employment polygraph examinations are a decision-support tool intended to add incremental validity to the personnel selection process. Problems stemming from the use of the polygraph may be related to misunderstanding of the polygraph test and to field practices surrounding the use of polygraphy in the police selection process. Potential problems can result from ineffective selection of test issues, poorly constructed test questions and misguided policies surrounding the use of the polygraph. The authors review the history of polygraph screening, research, and field practices, and suggest that using polygraph results alone to disqualify a candidate from employment is a misguided field practice. Suggestions are offered for maximizing the decision-support value of the polygraph. Polygraph examination targets are discussed, with emphasis on selecting actuarially derived predictors associated with increased success in law enforcement training and job performance. The authors provide recommendations for field practice, and propose that police psychologists may be most suited to effectively integrate the polygraph results and information into the hiring recommendation process.