We survey recent work on the Sealing phenomenon. Woodin shows that various forms of Sealing hold in a generic extension of the universe of sets in which there is a supercompact cardinal and a proper class of Woodin cardinals. Sargsyan and I study Sealing in hod mice and compute the exact consistency strength of Sealing. I will give background and state precisely these results. I will also discuss the impact of Sealing on the universe of sets and the inner model program.