The 31st Annual Meeting of the Division of Particles and Fields (DPyC) of the Mexican Physical Society was held at the José Ádem Auditorium in Cinvestav-IPN, Mexico City, Mexico, on 24-26 May 2017. We are extremely glad to have had a record of 180 participants attending the meeting, in which 82 presentations (39 posters and 53 talks including 40 contributed, 12 invited and a closing talk) were ... [Show full abstract] given. These numbers and the unquestionable scientific quality of the research work presented show the success of this meeting. In the days immediately before the meeting (22-23 May 2017) we organized a Tau Physics mini-Workshop, which can be considered the third edition of a series started in Krakow [1, 2], and where we had 12 invited seminars fostering discussions between the local Community working on Tau Physics and the invited foreign speakers, who participated in our national meeting as well. All presenters of both meetings were invited to contribute and roughly half of them accepted. We thank them for this effort, which made these proceedings possible.