As a native of Louisiana no longer living in the Bayou State, I often have an "envie" (that's cajun dialect for "yearning") for the food I grew up with. I got my first copy of this book in 1975 and have cooked with it ever since. It is particularly strong on the classic New Orleans recipes--oysters rockefeller, trout veronique, Bananas Foster--but also covers some basic stuff like how to make a good Bechamel sauce, hollandaise.
It is also quite good at Cajun cooking. Most people outside of Louisiana think you can make anything "Cajun" by dousing it with Tabasco--not so. It's a far subtler cuisine than that, generally no spicier than Szechuan and certainly less spicy than Thai. The recipes for Chicken & Sausage Gumbo, Chicken Macquechoux, and similar stuff have been used so often the pages are sticky with spatterings of oil and roux.
I prefer this GREATLY to Paul Prudhomme's book. (I have both and rarely use Paul's.) If you are interested in a strictly Cajun cookbook and not in something which has New Orleans cuisine, I might recommend Justin Wilson's Homegrown Louisiana Cooking. Still, The New Orleans Cookbook is by far my most-used Louisiana cookbook, and one of the most used cookbooks in my kitchen.