First in Chapter 2, we discuss the collisional relaxation of a strongly magnetized pure ion plasma that is composed of two species with slightly different masses, but both with singly-ionized atoms. In a limit of high cyclotron frequencies Ωj, the total cyclotron action Ij for the two species are adiabatic invariants. In a few collisions, maximizing entropy yields a modified Gibbs distribution of the form exp[-H/T_para-α1 I1-α2 I2]. Here, H is the total Hamiltonian and αj's are related to parallel and perpendicular temperatures through 1/T_(perp,j)=1/T_para+αj/Ωj. On a longer timescale, the two species share action so that α1 and α2 relax to a common value $\alpha$. On an even longer timescale, the total action ceases to be a constant of th...