In essence, this volume is an attempt to define French cuisine, French gastronomy, French cooking, and French food. Yes, now you can find the molecular gastronomy influence (look up nitrogen, liquid in this encyclopedia), and you can find ingredients sneaking in from each corner of the Earth, Pacific Island taro, South American tanko beans, and New Zealand spinach. Mole Poblano shows up and there's a turkey mole recipe. French cooking is not just the old cordon bleu, but the vocabulary of that sort of cooking, seasonal and fresh, elaborate preparations of few ingredients is the basis for this. The exquisite souffle section confirms that. Or turn to the basic cooking process/item of panada: seven recipes for the basic repertoire.
Each edition of the book has gotten larger, covering still "French" cooking but it's that subject which is getting larger. Larousse discusses the rodent, informing us that in 1870 Paris (under seige) rats were sold for 10-15 sous, and it discusses wine production in the United States. There's something for everyone who is interested in food.
Since the book is expensive, it's worth noting that most anyone who wants to save some money could sensibly consider the recent editions from 2001 or 2005, and if one is interested in the classic form of French cooking then the 1961 (first English translation) is also worth considering. Just don't complain about the use of butter or lard in the recipes.