How to calculate homology groups of spaces of nonsingular algebraic   projective hypersurfaces
  A general method of computing cohomology groups of the space of nonsingular algebraic hypersurfaces of degree $d$ in $CP^n$ is described. Using this method, rational cohomology groups of such spaces with $n=2, d \le 4$ and $n=3=d$ are calculated. 
Victor A. Vassiliev
math.AG