Notes on Sela's work: Limit groups and Makanin-Razborov diagrams
  This is the first in a planned series of papers giving an alternate approach to Zlil Sela's work on the Tarski problems. The present paper is an exposition of work of Kharlampovich-Myasnikov and Sela giving a parametrization of Hom(G,F) where G is a finitely generated group and F is a non-abelian free group. 
Mladen Bestvina, Mark Feighn