This book is the most autobiographical that Mary wrote. I won't go into any explanation of this, but if you read one of the biographies about her life, you won't need my help to find the similarities.
A huge weakness I have discovered so far is excessive narration and explanation of each character's emotional state, a fault Mary generally avoids in later novels. I really didn't need a minute-by-minute update of Elsie's fears and anxieties. At first this was interesting, but rapidly becomes annoying and redundant, as the characters are ruled by pretty much the same thoughts throughout.
Mid-way through the book, I just gave up and quit. Elsie is a total bore, a silly timid girl scared of her own shadow. When I started skipping paragraphs describing her doings and thoughts, I realized the book had ceased to entertain or enlighten. Leo and Helen are more original, but Mary just doesn't give them enough play.
And for Chrissakes, let the characters speak, instead of modifying their every pronouncement with a description of their emotional state. Such as - "She said, without sincerity." Or, "She said, with trepidation."
You may want this book to see how a great author like Renault started out writing boners. Writing is damned difficult work, and the only way to get good is to just keep doing it over and over throughout the years. It is one skill that seems to improve with age, unlike everything else.