TMBS and the Perilous Journey - by Trenton Lee Stewart

This is an author I'd love to meet.  If you've read his books, you'll understand, and if you haven't:  This guy is both incredibly smart and a terrific writer!  The sequel picks up where The Mysterious Benedict Society left off, and finds four interesting children coming together to solve a mystery that is far larger and more dangerous than they could have expected.  They must escape from the safety of their families and homes, head out across the ocean on their own, and travel to strange new lands in order to save their mentor and friend, Mr. Benedict, from certain doom at the hands of his evil mastermind brother. 

The writing in this book is crystal-clear, the characters full of character, and the plot interesting from the get-go, though moreso to those readers smart enough to have read the first book first.  The writing is a bit like Lemony Snicket's, though more challenging (and rewarding), and this would be a good series for the reader who has finished A Series of Unfortunate Events, and would like to try something along the same lines, but even more thought-provoking.  The book also resembles the Harry Potter series in a way, as the main characters keep learning more about themselves and each other, and finding ways to use their powers for good rather than evil.