We will briefly discuss Hecke’s central value formula and move on to the adelic setting in order to state Waldspurger’s theorem.

We will give a short introduction to automorphic forms and representations and proceed to state the orthogonal and unitary GGP conjectures.

We will present the theory necessary to understand the statement of the Ichino-Ikeda refinement of the GGP conjectures and time allowing give a sketch of the steps in the proof of the unitary GPP conjecture.