Earlier research on industry evolution has introduced a number of theoretical models of how industries evolve, and identified a number of factors driving this process. In general, however, much of the earlier topical research has focused on explaining the evolution of industries by the characteristics of the industry in question or the firms operating within it. One of the areas where little research exists is on the effects of other industries or organizational populations on the evolution of a particular industry. Thus, responding to calls for this type of research, this study aims at extending the knowledge of inter-industry or inter-population interactions both theoretically and empirically. The study builds primarily on organizational and community ecology, the only research paradigm that has systematically studied evolutionary interdependences between different types of organizational populations. Theoretically, the study introduces a novel theoretical framework of interdependences between organizational populations. In particular, the framework incorporates the view that a population niche is a multidimensional construct, and turns the basic level of analysis of interactions to the level of the niche dimension. A number of propositions are formulated of the effects of different types of niche dimension level interactions on vital rates of organizational populations. Empirically, the study examines ecological interdependences in a novel research context: the paper & pulp and the printing & publishing industries in four European countries - Finland, Germany, Sweden, and the UK - during 1950-2005. On the basis of historical narratives of the evolution of the eight separate industries, descriptive analyses of the resource flows between the industries, and the theoretical framework, hypotheses of the interdependences between the industries are formulated. By employing life-history data of the evolution of paper and pulp firms in the four countries, the hypotheses are then statistically tested. In general, the results show that paper & pulp and printing & publishing industries have affected positively on each other's vital rates. When it comes to the specific interactions between the industries in the four country setting, the results suggest that the interactions have been complex. For example, it is found that the interactions have not been bounded by geographic space, there have been differences in the strength of the interactions between the industries, and that the strength of the interactions has changed as a function of time.