Essays and notes based on meticulous research in a wide range of sources, many only recently available, provide a rich context for the documents.

The presence - or absence - of soil organic matter (SOM) has important implications for agricultural productivity. A database is included with the book, presenting tabular data for 34 sites in North America.

Illustrated with hundreds of Edison's drawings, these documents are further illuminated by meticulous research on a wide range of sources, including the most recently digitized newspapers and journals of the day.