Polynomial root-finding algorithms and branched covers
  We construct a family of root-finding algorithms which exploit the branched covering structure of a polynomial of degree $d$ with a path-lifting algorithm for finding individual roots. In particular, the family includes an algorithm that computes an $\epsilon$-factorization of the polynomial which has an arithmetic complexity of $\Order{d^2(\log d)^2 + d(\log d)^2|\log\epsilon|}$. At the present time (1993), this complexity is the best known in terms of the degree. 
Myong-Hi Kim, Scott Sutherland