One way to describe the character of Lio is dark. Also entertaining, twisted, amusing, weird, odd. A young boy whose world has aliens, monsters, robots, and the most interesting pets. And it's not his imagination.
Lio never speaks a word, the comedy is nearly all visual.
This edition is actually a collection from the first year of the syndicated comic strip. When compared to current strips, you can tell that Mark Tatulli was still finalizing how the characters looked. But that doesn't inhibit the enjoyment of the panels. His dad - who mostly appears in a tee, boxers and socks and has the same upward bangs that his son inherited - accepts his odd little boy. The cat, Cybil who usually uses the most interesting weapons in order to remind the humans he needs feeding. Lio's pet snake, spiders, and cephalopod. Classmates and bullies. The girl with the bangs covering her eyes that Lio has a crush on (she's not interested and destroys Lio's floating heart in a variety of interesting ways but he isn't discouraged).
To give an example: Lio is in bed, reading a book entitled "The Monster Under My Bed", notices a light under his bed, crawls underneath where the final panel is upside down with the monster reading a book entitled "The Weird Kid Under My Bed".
If you plan on reading about the adventures of Lio, having a off-kilter sense of humor certainly helps. Lio is available on-line on a daily basis.