Aspects of Axions and ALPs Phenomenology

The physics of axions and axion-like particles (ALPs) is enjoying an incredibly productive period, with many new experimental proposals, theoretical idea, and original astrophysical and cosmological arguments which help the search effort. The large number of experimental proposals is likely to lead to fundamental advances (perhaps, a discovery?) in the coming years. The aim of this article is to provide a very brief overview of some of the recent developments in axions and ALP phenomenology, and to discuss some relevant aspects in this important field. A particular attention is given to the definition of motivated regions in the axion parameters space, which should be the targets of experimental searches.