WE read about 30 books on the solar system. Some he was able to read to us.. some our dd7 read and a few we read to them. We than built a solar system. I think that following his interests more may be better than level 1 and 2 readers. I did look at the DG ( I think those were the non fiction readers) last week. I may have to go back and get some. I am wondering if there are any math reading books on this level as this is truly where his interest is. He told me yesterday, he wants to learn about the united america states over the summer (USA maps). So now I have been challenged to find inexpensive materials.