  In these notes we present the method introduced by Neeman of generalized side
conditions with two types of models. We then discuss some applications: the
Friedman-Mitchell poset for adding a club in \omega_2 with finite conditions,
Koszmider's forcing construction of a strong chain of length \omega_2 of
functions from \omega_1 to \omega_1, and the Baumgartner-Shelah forcing
construction of a thin very tall superatomic Boolean algebra.
