Nitrogen fixation is currently of great practical importance because the use of nitrogenous fertilizers has resulted in unacceptable levels of water pollution and the fact that these fertilizers are becoming steadily less economic both in cash terms and in utilization of fossil fuels for their manufacture.
If you ever wondered what Black Locust trees and White Clover had in common, this book spells it all out in chemical analysis, with graphs and diagrams, charts and lists like one would find in an academic biological science article.
It is all about the things depicted on the cover: nitrogen-fixing nodules of plant roots. Tiny little things, but without them, the earth would be a different place. With 217 pages of articles and then the references, the text is not easy to read, but worth understanding.