The Level Up series is a systematic, easy to understand guide for the beginning go player. There are 12 books in this series, divided into two sets of 5 books and a review book for each set of five. The books are very basic and written using simple explanations in easy to understand terms, very suitable for children. What is really different about this series is that they are all true workbooks. You are presented problems covering key concepts of Go and write your answer in the book. To check you answers you go to the following web site: http://baduktopia.dtrinks.de/ . The books are written for children like a comic book adventure, making it entertaining as well.
An adult beginner may not be interested in the comic portions of these books; however they will find that the lessons are just as effective for them as it is for a child. The publisher Baduktopia has a problem book out also, however I have been unable to find it. Yet the 12 books have quite a few problems as to keep you occupied for a while.