The stochastic limit of quantum theory [1] motivated a new approach to the renormalization program. Subsequent investigations brought to light unexpected connections with conformal field theory and some subtle relationships between renormalization and central extensions. In the present paper we review the path that has lead to these connections at the light of some recent results. , higher powers of white noise, central extensions.Dedicated to Igor V. Volovich with friendship and admiration for his scientific achievements 1. INTRODUCTION The stochastic limit of quantum theory [1] has led to a multiplicity of developments in physics and mathematics. In particular the quite nontrivial identification of classical and quantum stochastic equations with first order white noise Hamiltonian equations naturally rose the question of the meaning of higher order white noise Hamiltonian equations.Due to the identification of quantum white noise with the free Boson field (in momentum representation) this problem is equivalent to the problem of giving a meaning to nonlinear functions of the local quantum fields, i.e. to the old standing renormalization problem.The equivalence of this problem with that of constructing a continuous analogue of the * -Liealgebra of differential operators with polynomial coefficients acting on the space C ∞ (R n ; C) and of its unitary representations has been discussed in the paper [9] (continuous analogue means that the space R n ≡ {functions {1, . . . , n} → R} is replaced by a space of test functions {functions R → R }).In the present paper we will discuss the connections of this problem with that of central extensions of * -Lie-algebras.Since the simplest power higher that the first is the square, it was natural to choose this as the starting point to attack the general problem.In the case of finitely many degrees of freedom quadratic Hamiltonians are easily diagonlized by a Boglyubov transformation but, as pointed out in the paper [16], when one tries to apply this technique to the field case, a constraint appears in the form of an inequality which excludes the simplest example one would like to be able to deal with: the square of the local quantum field, i.e. of classical white noise.This remark convinced us that, for a successful attack the renormalization problem, a radically new approach to the problem was required.Such a new approach was proposed by Accardi, Lu and Volovich in the paper [15] and its basic new idea can be formulated in the following problem: first renormalize the Lie algebra structure (i.e. the commutation relations), thus obtaining a new * -Lie algebra, then construct (nontrivial) Hilbert space representations.In the same paper [15] the concrete realizability of the new approach was proved by explicitly constructing the Fock representation for the Renormalized Square of White Noise (RSWN).