Back in the 90's I used to read mystery books, I can't remember what they were called.?

Question

they had twin sisters that would solve the mysteries, but I can't remember who they are or what the books were called. Does anyone remember?

Answer 1

Are you thinking of the Dana Girls series? They were sisters, but not twins, I don't believe.

Answer 2

I used to read The Hardy Boys mystery books. The were closely related to the Nancy Drew mysteries that most of the girls read. But I believe you are talking about the Bobbsey Twins. The first books were more towards adventure. But as the popularity of Hardy Boys and Nancy Drew increased, the Bobbsey Twins series took on a mystery plot.