The Koren Talmud Bavli, Noé Edition, Vol 8: Shekalim, Daf Yomi B&W

Tractate Shekalim deals primarily with the finances and organization of the Temple. Based solely on content, this tractate rightly belongs in the order of Kodashim, the fift h order of the Talmud, which deals with matters pertaining to off erings and the Temple service. Nevertheless, Shekalim was placed in Mo’ed, the order dealing with the Festivals. This presumably has to do with the fact that the shekels were collected at a fixed time of the year, and the collection of the shekels would precede, and sometimes even determine, the dates for various aspects of the Temple service and related events.