Abstract: I will present a recent extension of the Veneziano and Shapiro-Virasoro amplitude to the case of arbitrarily excited strings (AES) in critical bosonic string theory. I will also discuss several novel applications, such as the absorption universality emerging from the absorption cross section of AES and the emission rate of AES with particular focus on the photon (and graviton) emission spectrum. Finally I will comment on the spin multipole expansion and the classical limit of three-point Heavy-Light-Heavy string amplitudes where the heavy states belong to both leading and sub-leading Regge trajectories.