Abstract: We recall the basic definitions of the two concepts and show the strong relations between them. We establish (almost) reducibility methods to obtain the dynamical properties of q-p SL(2,R) cocycles and then study the spectral theory of 1-d q-p Schrödinger operators. For instance, in the local finitely differentiable case we will show the process of proving the 1/2 Hölder continuity of Lyapunov exponents and the integrated density of states by almost reducibility.