The document discusses several important source books of Materia Medica in homeopathy. It describes 7 seminal works: 1) Fragmenta de Viribus Medicamentorum Positivis (1763) by Hahnemann, containing symptoms of 27 remedies. 2) Reine Arzneimittellehre (1811-1833) by Hahnemann in 6 volumes describing drug effects. 3) Die Chronischen Krankheiten (1828-1839) by Hahnemann observing remedies on sick people. 4) Encyclopedia of Pure Materia Medica (1874) by T.F. Allen describing 1039 remedies over 12