Bosonic String Dynamics

String Theory is a hot topic of physics and mathematics. For the former, it stands as a huge sandbox where the formulation of difficult problems can be simplified and their hard computations carried out. For the latter, it stands as a direct contribution upstream, going from physics to maths, rather than the usual other way around. These notes provide a comprehensive review of the bosonic string action, the entering point of String Theory, and also covers the resulting equations of motion and the effective mass of open and closed strings.