Is it the mission of Christianity only to save the souls of those whom we can persuade to come to church, or is it equally part of our mission to Christianise society? Father Michonneau and his collaborators in the parish of St Colombes in Paris have long been convinced that too exclusive a concentration on the first of these tasks is responsible for the relative failure of the Church among the industrial masses of the continent. In his parish, a few years ago, not more than five per cent of the total population could be regarded as practising Catholics. His book is an impassioned plea, fully supported by the late Cardinal suhard and blessed by Archbishop Cushrng of Boston, for the adoption of more realistic methods in dealing with such a situation. To begin with, they were convinced they had no right to spend all their time attending to the needs of the five per cent who were faithful, and forgetting the ninety-five per cent who were growing up with little knowledge of Christ and no knowledge of the Church.