Introduction: needs, ways, and obstacles to discovery / J.D. Bu'Lock -- Principles and problems of selective isolation of microbes / S.T. Williams and E.M.H. Wellington -- Culture preservation and instability / A. Dietz -- Design of culture media capable of provoking wide gene expression / R. Hütter -- Novel approaches to metabolite screening / H. Zähner, H. Drautz, and W. Weber -- Screens for pharmacologically active fermentation products / R.L. Hamill -- Target directed antimicrobial screens / I.D. Fleming, L.J. Nisbet, and S.J. Brewer -- Inhibitors of antibiotic-inactivating enzymes / J.D. Hood.