I am trying to dig up the name of a novel-series I read when I was a child (early 90's) but I simply cannot recall either the name of the writer nor the name of any of the books.
The series has a young boy in the center who is accepted into a conclave of Librarians who travel the universe in a massive spaceship. The members of the conclave value knowledge above all else and during the books they visit different worlds where each world presents a new challenge in regards to corrupt governments, dormant threats and so on. The Librarians "battle" these problems using their vast knowledge and skills.
The boy is followed by a sort of bat-like dog throughout the series and the animal is present on all the book-covers in the series.
I recall one book taking place in a vast sea-dominated world and another on a wood covered planet... but apart form that I am at a loss.