Topics in Asymptotic symmetries and infrared effects

In this Ph.D. thesis we aim, first, to review the main aspects of the above-described connection between asymptotic symmetries and observable effects in the context of gravity, electromagnetism and Yang-Mills theory in four dimensions and, second, to present original results concerning the extension of this program to the case of arbitrary dimensional spacetimes and to higher-spin gauge theories. Motivated by the appeal possessed by memory effects in connection with the asymptotic structure of gauge theories, we present a collection of results concerning memory effects in higher-dimensional scalar, electromagnetic and non-Abelian theories and on their interpretation in terms of residual symmetries acting at large distances in even dimensions. [...]