What is a short summary of Act 1?

Do you mean chapter 1?

Milo is a young boy who never quite knows what to do with himself. He does not care for school or being out of school, and he thinks everything is a waste of time. No one can tell him why attaining knowledge even matters. He feels unhappy all the time.

Milo comes home from school one day and dejectedly realizes he’s in for another long afternoon. He thinks the things he owns are boring, but then he sees something he has never noticed before – a large package in the corner. It is labeled “FOR MILO, WHO HAS PLENTY OF TIME” (12).

Milo cannot figure out who sent it and why, but reads the envelope that accompanies it. The letter says the package contains a genuine tollbooth, three precautionary signs, coins for paying tolls, and one map and one book of rules and traffic regulations.

Milo sets to building the tollbooth and it is not long before it is completed. He considers it strange and wonders why there is no highway to go with it, but nevertheless sets up the three signs that inform he should “SLOW DOWN APPROACHING TOLLBOOTH,” “PLEASE HAVE YOUR FARE READY,” and “HAVE YOUR DESTINATION IN MIND” (14). The map is lovely but Milo has never heard of any of the places on it. He reads the word “Dictionopolis” and decides he might as well go there.

He dusts off a car of his, takes the map and rulebook, and puts his coin in the tollbooth. All the while he hopes it will not be a dull afternoon.