This is dense! I'm spending about 10 minutes per page.

I'm not convinced it's not me, rather than Logical Labyrinths, that's dense.

I felt a bit bad when I missed the rule that no one could say "I am a knave." That felt bad.

Why? That's the whole trick to the first problem!

I'd say the whole point of the first half of the book (i.e. the part on propositional logic) is to get you to work it out by case analysis (i.e. truth tables).

I think because in retrospect it was obvious and with a bit more care and thought about it I could have figured that out. My problem has always been that I fly past things too quickly. Ready, Fire, Aim as my parents would say.

It might make you feel better to re-read the first two problems, because the second one makes very clear that Smullyan didn't expect you to just know the "No native can claim to be a knave" rule off the cuff. :-)