Madan Puri along with P. K. Sen is one of the more well-known researchers in the theory of nonparametric statistics. There are not many texts on multivariate nonparametrics. Rank methods are not uniquely extended to the multivariate setting, so the methods are difficult and involve more that just multivariate ranking mapping of the data. If the reader is interested in multivariate statistics but want to learn more general theory than the traditional methods that are based on multivariate Gaussian assumptions, this is one of the best books to look to.