A Series of Unfortunate Events! The Miserable Mill is the fourth book in the series and The Austere Academy is the fifth book in the series. The books were written for children and teens but can also be enjoyed by adults.
The whole storyline revolves around a brother and sister who lose their parents while they are still children. Their parents were very wealthy and their guardian Count Olaf has rather dubious motives for the kid's wellbeing.
The 13 books in order are (along with release date):
1) The Bad Beginning (1999)
2) The Reptile Room (1999)
3) The Wide Window (2000)
4) The Miserable Mill (2000)
5) The Austere Academy (2000)
6) The Ersatz Elevator (2001)
7) The Vile Village (2001)
8) The Hostile Hospital (2001)
9) The Carnivorous Carnival (2002)
10) The Slippery Slope (2003)
11) The Grim Grotto (2004)
12) The Penultimate Peril (2005)
13) The End (2006)
https://en.wikipedia.org/wiki/A_Series_of_Unfortunate_Events