This epic textbook took me around 5 years to get through, and is the best language-learning book I've come across. Every word in the book is in French, and yet it takes you from zero knowledge to a high level of reading in an engaging, fun way. The vast majority of the book is a running story about a couple of families in France and Algeria, with some traditional stories packaged within, and these help set the scene and give an insight into French life and history while learning the language.
I'd recommend this to anyone wishing to learn French, even if it's now 70 years old.