Effective Microorganisms, effectiveness and practice. The EM user?s guide gives a well-founded view of the diverse effects of ?Effective Microorganisms (EM)? and their use to combat current environmental problems, in the garden and in agriculture, in the home and in industry. Its 300 attractively designed pages provide a unique and illustrative insight into the extensive research that specialist journalist Anne Lorch has conducted on EM. 300 pages.