Lawrence Guth continues MIT's 18.156 Projection Theory with a lecture on sharp projection theorems, opening a study of recent breakthroughs by Orponen-Shmerkin and Ren-Wang. Guth sets up the problem of sharp bounds in projection theory and demonstrates a technique for building a sharp bound out of repeated applications of a non-sharp one, introducing Beck's theorem along the way as a key ingredient. The lecture is chalkboard-style and assumes familiarity with the course's earlier material on projections of sets in the plane and higher dimensions. As lecture 22 in a graduate sequence, it is aimed at students already versed in harmonic analysis and geometric measure theory rather than newcomers, and it covers the opening stretch of a multi-lecture treatment of these recent results.