The title, at least, is broadly accurate: this is a biography of Daphne Du Maurier, interspersed with biographical details regarding her sisters. While the second of the three sisters became famous and made a noteworthy contribution to literature, the other two did not make comparable contributions. Nor are their lives particularly fascinating; all three sisters were born and bred to great privilege, which they and the biographer are happy to dwell upon at great and tedious length, and all clearly felt comfortably entitled thereto. Unsurprisingly, their life spans consist of a long unspooling of expensive and glamorous vacations, a predictable succession of love affairs, and periodic periods of grief when each in turn of their preferred breed dogs met their expected demise.
Inexplicably, Angela stubbornly persisted in spawning a fleet of awful novels, undaunted by the merciless spanking delivered to each one by critics, along with the inevitable comparisons with Daphne's work. Daphne married a military man and spawned children and books, with most of her devotion reserved for the latter; she too had many love affairs, but her singular devotion in life was reserved for a mouldering old house, into which she poured endless amounts of her plentiful money and time. Jeanne painted and raised farm animals in seclusion. The less said there, the better.
The only rather interesting fact concerning this trio of upperclass twits - and this only from a prurient perspective - is that all three sisters were, according to contemporary definition, lesbians. And all three definitively and repeatedly refuted this label. In fact, a great deal of their surviving correspondence, of which there is a lot (when all is said and done, they were all certainly writers), is devoted to a never-ending and unconvincing series of sophistric contortions about why the dreaded "L word" (Daphne referred to it specifically in that way) did not apply to them. Methinks the ladies doth protest too much.
The evidence - and there is a lot of it, both on paper, photographic, and that of multiple eye witnesses - clearly shows that they had romantic-sexual relationships and affairs with women throughout their long lives, and that these were the primary foci of their psycho-sexual yearnings. Sadly, all three were so steeped in the traditions and mores of the time and place of their upbringing, that they were never able to fully reconcile themselves with their sexual identities. Also, their father, a conceited and popular actor-impresario to whom they were all utterly loyal and blindly devoted, despite the fact that he was a domineering philanderer who extolled the possession of good looks and splashy charm above all other human qualities, was a virulent homophobe. His influence is most probably the primary source of their internalized sexual self-loathing as well as their lifelong snobbery and general lack of empathy towards humans (they were, on the other hand, totally uninhibited when it came to dogs, landscapes and large estates). This contradiction and struggle provides for the only true point of substance or interest in the otherwise tedious tale of the trio's trials and tribulations*. I'm forced to admit that they make for a solidly unattractive tribe, and I am rather relieved to be done with them. As to the writing, it is perfectly adequate and better than the average tabloid tale-telling; it might have been directed elsewhere with more fruitful results.
*I'm being utterly facetious when I refer to trials and tribulations, since it's difficult to make the argument that any of these three women experienced anything of the sort, either by the standards of the times in which they lived, or ours. I just couldn't resist the alliteration. Even though they lived through both World Wars, it is clear, despite the biographer's mincing delicacy in so describing, that their socio-economic privilege afforded them an unparalleled (aka, revolting, shocking, indecent, unfair, classist, unwarranted) degree of comfort and safety that very few of their more "common" contemporaries experienced during those times. Like everything else that came to them in life, the sisters (with the occasional exception of Jeanne, who spent WWII engaged in an extreme form of health-impairing potato-farming) breezily accepted it as a form of tribute that they deemed to be the natural due of the supposedly superior breed known as the Du Mauriers.