The writing talent alone of the Mankiewicz Brothers – Herman and Joseph – is overwhelming.

Younger brother Joseph won academy awards for writing and directing, particularly for the verbal fireworks of All About Eve, and Herman laid the basis for the cinematic masterwork Citizen Kane.

That legacy alone would satisfy most people. Yet the Mankiewicz Brothers produced so much more. Their creative fingerprints can be seen on films as diverse as The Philadelphia Story, Duck Soup, Dinner at Eight, The Ghost and Mrs Muir and even The Wizard of Oz.

Lured by large salaries, the brothers left the intellectual life of New York for the well-paid work of Hollywood.

Their writing was considered to be down market to the intellectual heights of Broadway, but it would prove to be a fruitful decision.

While each brother was talented and successful, each would rise and then suffer a painful decline in a different way.

Herman wasted his talent through alcoholism and Joseph had to suffer a bitter decline in his career as he grew older.

Author Sydney Ladensohn Stern has a wide range of writing interests, having produced books about the feminist leader Gloria Steinem and the toy industry.

She has the novelist’s gift of placing anecdotes in a flowing narrative to deliver a fine story. With each anecdote, she opens up fascinating lines of thought and she manages to do this repeatedly throughout the book.

While each brother was talented and successful, each would rise and then suffer a painful decline in a different way.

Moreover, Stern has revealed a valuable undercurrent of Hollywood history.

Ethan and Joel Coen are only the latest of a long history of brothers – and some sisters – who have shaped Hollywood. The list extends right back to its origins when Cecil B. DeMille and his brother William worked together in a shed in a small rural town called Hollywood in the 1910s.

Perhaps other writers will follow in her footsteps and look at the role of sibling rivalry and co-operation has worked in the development of American cinema.

Author-journalist Stern has written a groundbreaking dual biography, with an excellent balance between the stories of two brothers. It is hard to see how the book can be bettered.