preface 1 parameter spaces: constructions and examples a parameters and moduli b construction of the hfibert scheme c tangent space to the hilbert scheme d extrinsic pathologies mumford's example other examples e dimension of the hilbert scheme f severi varieties g hurwitz schemes basic facts about moduli spaces of curves a why do fine moduli spaces of curves not exist? b moduli spaces we'll be concerned with c constructions of mg the teichmiiller approach the hodge theory approach the geometric invariant theory (g.i,t.) approach d geometric and topological properties basic properties local properties complete subvarieties of mg cohomology of mg: hater's theorems cohomology of the universal curve cohomology of hfibert schemes structure of the tautological ring witten's conjectures and kontsevich's theorem e moduli spaces of stable maps techniques a basic facts about nodal and stable curves dualizing sheaves automorphisms b deformation theory overview deformations of smooth curves variations on the basic deformation theory plan universal deformations of stable curves deformations of maps c stable reduction results examples d interlude: calculations on the moduli stack divisor classes on the moduli stack existence of tautological families e grothendieck-riemann-roch and porteous grothendieck-riemann-roch chern classes of the hodge bundle chern class of the tangent bundle porteous' formula the hyperelliptic locus in m3 relations amongst standard cohomology classes divisor classes on hilbert schemes f test curves: the hyperelliptic locus in m3 begun g admissible covers h the hyperelliptic locus in m3 completed 4 construction of m3 a background on geometric invariant theory the g.i.t. strategy finite generation of and separation by invariants the numerical criterion stability of plane curves b stability of hilbert points of smooth curves the numerical criterion for hilbert points gieseker's criterion stability of smooth curves c construction of mg via the potential stability theorem the plan of the construction and a few corollaries the potential stability theorem limit linear series and brill-noether theory a introductory remarks on degenerations b limits of line bundles c limits of linear series: motivation and examples d limit linear series: definitions and applications limit linear series smoothing limit linear series limits of canonical series and weierstrass points limit linear series on flag curves inequalities on vanishing sequences the case p = 0 proof of the gieseker-petri theorem geometry of moduli spaces: selected results a irreducibility of the moduli space of curves b diaz' theorem the idea: stratifying the moduli space the proof c moduli of hyperelliptic curves fiddling around the calculation for an (almost) arbitrary family the picard group of the hyperelliptic locus d ample divisors on mg an inequality for generically hilbert stable families proof of the theorem an inequality for families of pointed curves ample divisors on mg e irreducibility of the severi varieties initial reductions analyzing a degeneration an example completing the argument f kodaira dimension of mg writing down general curves basic ideas pulling back the divisors dr divisors on mg that miss j(m2,1 w) divisors on mg that miss i(m0,g) further divisor class calculations curves defined over q bibliography index