My son read some of these books about a year ago. I'm sure a lot of the content was over his head, but he enjoyed the books enough to continue reading. I'm exp

My son read some of these books about a year ago. I'm sure a lot of the content was over his head, but he enjoyed the books enough to continue reading. I'm expecting him to re-read the whole set at least twice. (BTW if you're in the UK, you can often find the complete set of 10 books on eBay for £12 including delivery.)