The text in this book is a little more complicated that the other book that I read but that is probably because the previous book was teaching children prepositions where as this book has a bit of a moral undertone. It seems that by the time children get to this level of reading it is more about teaching morality as opposed to simply teaching a child how to read.
I guess in one aspect the book is teaching us that playing dirty tricks on people is not conducive to good relationship, and if you keep of doing it then you could quite well land up in trouble. Obviously the idea of trouble in this book is analogous to prison, since Gus the firefly is imprisoned in a jar, after being caught, and taken off to an unknown destination.
However, another idea that comes out of this book is the idea that language needs to be used wisely. Language is power, and being able to use language effectively empowers people. This is one of the reasons that there is a push for the education of women in developing countries as by giving women the right to education empowers then to be able to determine their own destiny as opposed to having their destiny determined by another.
However, this book also shows us that with great power comes great responsibility. Sam teaches Gus how to write, and upon learning how to write, he immediately goes away and begins to abuse this power. The abuses aren't even all that innocent, such as causing ground and air traffic chaos, as well as advertising free movies. Yet, while he may have got away with some jokes, his actions eventually annoy enough people that they decide that it is time to put a stop to it. As is said on the Big Bang Theory – it is okay to be smarter than everybody else, just don't rub their nose into it.