2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/182581In this talk a short overview of $η$ and $η'$ decays is given with an emphasis on what can be learned for the strong interaction from them. The talk consists of a short introduction to ChPT, a discussion of $η\to3π$ beyond $p^4$ and some of the physics involved in $η'\toηππ,3π$ as well as an overview of anomalous processes.13 pages. Talk presented at the Eta'05 Workshop on production and decay of $η$ and $η'$ mesons 15th--18th September 2005, Jagellonian University, Cracow, Poland. v2 :Changes in figures, misprints corrected, reference addedHigh Energy Physics - PhenomenologyNuclear Theorytext