My paperback copy of this book is falling apart with use - it is one of my favourites - and now a hardback is available. If you like Elizabeth David you will love this, it is intelligent, eloquent and very evocative. The recipes are detailed but not strict. There is a lot of emphasis on the nature of ingredients and on general method, which invites improvisation and confident invention.
The 'simple' food of the title is simple in the sense that it is not the over-elaborate food of urban restaurants, it is about the best home cooking which you can still find in unpretentious small town cafes. But simple does not mean artless, it is about well chosen ingredients combined with great technical understanding and real sensitivity. This is French food at its best, and an inspiring book for adventurous cooks.