“…The so-called fourth moment phenomenon was first discovered in Nualart and Peccati (2005), where the authors proved that a sequence of normalized random variables, belonging to a fixed Wiener chaos of a Gaussian field, converge in distribution to a Gaussian random variable if and only if their fourth cumulant converges to zero. Such a result constitutes a dramatic simplification of the method of moments and cumulants [see, e.g., Nourdin and Peccati (2012), page 202], and represents a rough infinite-dimensional counterpart of classical results by de Jong; see de Jong (1987,1989,1990), as well as Döbler and Peccati (2017a), Döbler and Peccati (2017b) for recent advances. A particularly fruitful line of research was initiated in Nourdin and Peccati (2009a), where it is proved that the results of Nualart and Peccati (2005) can be recovered from very general estimates, obtained by combining the Malliavin calculus of variations with Stein's method for normal approximation.…”