The Shepherd's Crown is Terry Pratchett's last book, finished just before he died. It is a Discworld novel (#41) and a Tiffany Aching novel (#5), and is classified as young adult fantasy.
The story starts with a tragedy -- Granny Weatherwax, being really quite old, finally passes away. This causes quite a stir among the witches, but particularly affects Tiffany, as Granny has named her as the heir to her steading, meaning that Tiffany now has two steadings, each one more than enough work for a single person.
Tiffany finds herself defending her position as the presumed head witch (if there was such thing, which there isn't), grudgingly looking for an apprentice or two, and dealing with a possible invasion of elves, all while trying to take care of two villages worth of sick, pregnant, and sometimes simply unwise humans.
This book continues the ongoing change in tone in the Discworld novels, from madcap comedy to a calmer world much like our own -- although, certainly, our own of about 200 years ago. There's some good historical references, although no major advances in technology, as that is not Tiffany's role in the Discworld. And of course, the elves, the Igors, and the wizards are still around, they are simply becoming less stereotypical characters written for laugh lines and more like real people.
This book was finished up in a hurry, due to Terry Pratchett's declining health. The novel is clearly unpolished, needing some editing down of the dialog and some polishing up of the wording. While he was able to complete the entire storyline with all necessary bits, Pratchett did not get the time he would have wanted to fine-tune it, and it shows. However, it is still a satisfactory Discworld novel, and an interesting view into what a novel one small step away from completion looks like.