Traditional questionnaire and interview approaches, following a preestablished protocol, do not allow for really grasping the originality of the ideas of the poorest among us, particularly with regard with what they can teach us. Yet their contribution is essential to furthering knowledge and advancing humanity. In order for them to speak up, it is necessary to creates sites and a climate in which they feel comfortable. Through illustrations, this article describes the approach favoured by Joseph Wrésinski and the Movement Atd Quart Monde as a means of drawing out the contribution of the poor to knowledge - a knowledge in and by action approach.