Introducing the closing, shortest tractate in Moed. On the holiday pilgrimages to Jerusalem with the specific sacrifices that were required for those days. What it means to celebrate underlies these factors of the mitzvot of the day, in term so rejoicing. Also, the mishnah that introduces the tractate, the mitzvah of "re'eiah" - going up to the Beit HaMikdash on the holidays. Everyone is obligated in this mitzvah - except for the long list of those who are not. Plus, disputes by Beit Hillel and Beit Shammai regarding how we define a "katan," a minor, with regard to this specific going up to Jerusalem. Does the child need to be able to walk or not, for example?