Quick-take: Thankfully, less commentary.
Alcatraz Smedry and crew is off to infiltrate another dangerous library to uncover secrets and critical plot points.
Another family member joins the crew. This one is a very short uncle. As a short person myself, I am a bit annoyed that the short people are most often chosen for comedy roles, and the small uncle actually echos the sentiment... in a frequently comedic way.
Like the previous book, the book is in 1st person narration from the perspective Alcatraz like it was an autobiography. He frequently assures the book is completely true unlike the non-fiction section of the evil librarians...
The breaks for author commentary are simply not that entertaining. I did not care for them in the previous book, and I do not care for them much here. However, it does seem like they are far less frequent. Just how many times will Alcatraz make the same joke about being a nice person because he wrote in a cliffhanger?
Score: 4/5. There are only 5 short books in this series. Might as well finish it.