Difficulty level, roughly compared to ABRSM exam grades. 0 is beginner, 9 is advanced (beyond grade 8).
This is a great book with 6 lovely tunes for an elementary flautist written in a wonderfully easy style. There is an accompaniment CD and the book is beautifully produced. No one will buy it though because it is ridiculously overpriced. I often wonder why this type of French music is issued here, as it's always so prohibitively expensive but if you do have loads of money to spare this book would make a great present.