I have read most of The Boxcar Children series, by Gertrude Chandler Warner.  The first book in the series is not a mystery book, the other books are.   Henry, Jessie, Violet, and Benny Alden live with their rich grandfather after their parents died in a car accident.  They travel to many places including Niagra Falls, the Whitehouse, and many other well-known places, and solve mysteries.  The first about ten books are written by the original […] Read more »