I got this from my local library out of curiosity. I got a companion volume to it also, but both volumes contain pretty much the same thing: the Jane Austen works that didn't quite make it big!
This volume contains what is commonly called Sanditon, which was the novel Austen was working on when she died. Her own title for it was The Brothers. Many people have pretentiously tried to 'continue' this novel since it was incomplete, but unsurprisingly, it has never taken off as her other major works did.
It contains Lady Susan, about a very aggressive and self-possessed older woman, which Austen finished right before she began work on "Elinor and Marianne" which came to be known as Sense and Sensibility, and following which she began her second full-length novel, "First Impressions" which is known today as Pride and Prejudice.
It also contains The Watsons - the story of Sherlock Holmes's famous companion before the two of them met. Just kidding! Seriously, The Watsons is about an invalid and impoverished clergyman and his four unmarried daughters. Sounds remarkably like Pride and Prejudice, doesn't it?!
Additionally this collection contains what's come to be called "Juvenilia" which is material Austen composed when she was a juvenile. Some of this is really quite amusing. It also contains Austen's tongue-in-cheek 'plan of a novel' and opinions she evidently collected, expressed by friends over her (then) recently published work such as Mansfield Park and Emma.
I recommend this for real fans of Jane Austen.