Der Regenwurm (The Earthworm) was self-published by Gustav von Heyer in Hamburg, Germany in 1974. This printed publication is an excerpt of his book "Die Revolution beginnt im Garten" (The Revolution Starts in the Garden).
The publication consists of 46 pages (text and fotos). The text is in German language and describes in detail the considerable advantages of ecological agriculture with the assistance of earthworms.
The publication presents detailed instructions how to install your own breeding of preferable Red Wiggler worms as effective organic fertilizers.