This talk was given by both Tina Rasmussen and Stephen Snyder: how the jhanas fit into Buddhist practice; overview of the entire samatha practice; the three types of concentration; and differences from other practices.
Energy is a factor that is useful for preventing or overcoming unwholesome states of mind and for cultivating wholesome states of mind. A joyful mind is a natural outcome of this unfolding prcess that leads to freedom and enlightenment.