Book knowledge is the ability to recognize book formats and purpose. Early readers learn how to hold a book properly, to read English from left to right, how pictures supplement the story, and that books have basic components such as a front and back, spine, pages, covers, and more. Children automatically learn these things at a conceptual level long before they understand the purpose of each component.
With adaptive learning, the programs won't move on to the next level until your child has a firm grasp on the current material. The online games will be a wonderful way for your child to catch up on basic arithmetic concepts and be comfortable using them across applications.
By the time your child is ready for kindergarten or school, they should be able to recognize their own name and other simple written words. The sounds of each letter of the alphabet should be familiar to your child, and they should understand the principle of reading from left to right, which way to hold a book, and possibly even be starting to read three and four-letter words.
These are basically digital versions (like ebooks) of worksheets that can be bought and downloaded to your computer from the internet or from CDs and then printed out. The advantage is that you can print out whichever sheet you wish. If you need to re-inforce a certain concept more you can usually print out that sheet again. Of course you will therefore need to have a computer and a printer.