This book offers a collection of studies on various organizations' efficiency, criteria for evaluating efficiency, together with tools and methods for measuring efficiency. The articles included present an interdisciplinary look at efficiency, its essence and the principles of its measurement. They represent an attempt to seek the conceptual boundaries of efficiency, i.e. to clarify this abstract and multidimensional concept including its relation to innovation, competitiveness and intellectual capital. The contributions also identify a broad spectrum of conditions for achieving efficiency in various types of organizations and systems (e.g. health care, hybrid organizations, non-profit organizations), representing various industries (e.g. insurance, banking, tourism, agriculture).