This book deals with the identification of nonlinear systems structured in blocks. The considered models can involve memory nonlinear operators. The latter may be of backlash and backlash-inverse type. Then, the nonlinear operators are characterized by their parametric bordering lines which presently are allowed to be invertible and crossing, making possible to account for noninvertible general-shape static nonlinearities. To the knowledge of the author, the linear dynamic subsystem is not necessarily parametric but BIBO stable. This latter may be of entirely unknown structure. In this book, we present simple strategies for identifying nonlinear systems structured in blocks using several of techniques and tools.