The Michelin Red Guide is the red-covered book that comes out annually, listing the "best" restaurants and hotels across the land. Initially covering only France, The Michelin Red Guide today (2010) reaches out to 23 countries across the rest of the world.
"Good meals at moderate prices". The Michelin Bib Gourmand is a guide to the best affordably priced restaurants in France, where the value for the price is the critera.
The Bib Gourmand list is a subset of the current Michelin Red Guide: The restaurants in the Bib Gourmand guide are those listed in the Red Guide with the Bib Gourmand logo, but they do not necessarily have the coveted Michelin Star.
Nothing to do with restaurant star systems, the narrow-format Michelin Green Guides are published for, and about, different regions of France, and for some major cities, From Paris to New York. Each guide has amazing information about the title subject, not only the sites and museums, but historical, geographical and any other information relevant to that place.
We were personally disappointed when, several years ago, the illustrations in the Michelin Green Guides changed from pen-and-ink line drawings to color photographs. Still, the green guides make fascinating reading, even if you're not intending to visit a place.