I thought Sir Reginald's Logbook was very funny. The illustrations were hilarious, and the text couldn't have stood without them. I loved Sir Reginald, although he's probably a possible candidate for an assisted living facility, and his family really needs to start looking into that option. He's just a great literary character, period!
Adults will appreciate this story, but I think it may be a little over a kid's head. My niece "got" it once I explained to her that Sir Reginald had an active imagination, and that on each page reality was depicted beside "Reginald's World." Once she had that down she found it to be a pretty funny book.
The subtext of this story is Sir Reginald's real story. Kids may have a tough time picking up on this "other" story, so I think this book has a real potential to get a full spectrum of reactions from kids. It's a really cute book, but parents will know best whether or not their kids will "get" it.