Sometimes we need to go back to the basics. Some grand concepts are often used to build upon them apparently sophisticated models and explanations. However, those basic concepts go often unexplained. In this section, I would like to provide critical short overviews of some of the terms I deal with in my research. Most of them are actually contested terms and not as taken for granted as one would assume after reading much of the literature. I would like to provide at a glance some of the main discussions surrounding terms such as migration or diversity, as well as a basic list of references I have found useful to think critically about how I engage with concepts which are, please let do not forget this, socially and politically charged and, more importantly, the way we talk about such concepts DOES affects many people’s lives.