Book excerpt: Introduction: Big Moll and the science of scientific charity -- "Armies of vice": evolution, heredity, and the pauper menace -- Friendly visitors or scientific investigators? Befriending and measuring the poor -- Opposition, depression, and the rejection of pauperism -- "I see no terrible army": environmental reform and radicalism in the scientific charity movement -- The potentially normal poor: professional social work, psychology, and the end of scientific charity.