Riverdeep, the Novato, Calif.-based software publisher of such popular series as Reader Rabbit and Carmen Sandiego, has formed a book division that will launch its first titles this summer. Learning Company Books is being headed by Eric Stone, a former general manager of software for the Learning Company, and will publish titles for both the trade and schools.

The book line will be connected to Riverdeep's software products and will be series-based, but Stone stressed that children will not need to be familiar with the software to understand the books. The first list will include more than 20 books. Titles for preschoolers will mostly be activity books, while titles geared for fourth and fifth graders will be mostly storybooks.

The book division will use Riverdeep's existing relationships to distribute its titles to such outlets as warehouse clubs, discount stores and schools and is building a sales team to reach the bookstore market. A staff of seven will be dedicated to Learning Company Books, but the unit will draw on the resources of other Riverdeep subsidiaries, which include The Learning Company, Broderbund, Edmark and Teacher Universe. Stone expects to grow the Learning Company Books' list 15%— 20% over the next several years.