This book was fairly heavy-going. It's not really a biography of Flaubert. It's a book about Gustave Flaubert, the author of Madame Bovary. The last 100 pages of the book are a discussion of Madame Bovary. The book never reaches the end of Flaubert's life in 1880.
There is hardly any discussion (perhaps it would be more accurate to say no discussion) of Flaubert's relationship with his mother with whom he lived his whole adult life until she died in 1872. There is nothing about what influence his relationship with his mother might have had on his creative life, on his difficult relationships with women, or on his life generally.
There are many quotations in French from Flaubert's writing without translations into English. The reader of English who doesn't read French misses out on the benefit what these quotations are meant to illustrate. Strangely, however, there are other quotations from Flaubert's letters, for example, that have been translated into English.