It's a great book, however it's not well suited for children learning to read. I found it far more advanced to previous level 1 readers that I've bought my son, and all though it was a little overwhelming, he still enjoyed it being read to him and loved the pictures.
This is a great learning to read book. It is great for a preschooler. My son is excited about it, loves learning about rockets and spaceships, and is reading some words from it. Great book for your little scientist.