The astronomical community’s interest in Li continues to be vastly disproportional to its small abundance. The Li content of stars in the Galaxy links together several different research fields; from cosmology and Big Bang nucleosynthesis, to cosmic ray spallation in the interstellar medium, to mixing processes in stellar interiors, and even the presence of exoplanets. I will describe the intricate abundance patterns found for stars in different evolutionary phases and how the fragile nature of this light element makes it an excellent diagnostic tool for late-type stellar evolution all they way from the pre-main sequence to the tip of the asymptotic giant branch. I will further discuss some famous problems related to Li production and depletion and potential solutions in the light of improved models of stars and their spectra.