abstract: The study of modules of logarithmic vector fields and forms on hyperplane complements now has a 30-year history that has revealed some interesting subtleties. For example, a famous formula of Solomon and Terao expresses the characteristic polynomial of the arrangement (matroid) in terms of a specialization of the Hilbert series of modules of logarithmic differentials: however, the Hilbert series of such a module is not uniquely determined by the matroid. I will describe some recent results that give new relations amongst the Chern classes of sheaves of logarithmic forms, in some cases leading to explicit formulas and a "geometric" explanation of Solomon and Terao's formula. This is joint work with Mathias Schulze.