Methodological problems intrinsic to suicide prediction are discussed. The research on suicide predictive signs derived from attributes of the suicidal person, his behavior & surroundings, and on predictive instruments is reviewed. The results of these researches are equivocal, in that neither single signs, standard psychological tests, clinical judgements, nor scales are found to be predictive. Scales are shown to offer the best predictions. It is proposed that scales be better constructed.