It is the disagreement amongst the advocates of different approaches to problems or solutions which hinders the formation of any consensual strategy and the mobilization of adequate resources. That is why the "Encyclopedia" uses an approach that is as general and minimally structured as is feasible without losing coherence and utility. The intent is first to contribute to clarify the nature, extent, and interrelationships of problems and solutions. Even the distinction between problems and solutions is not always clear. For instance, housing an increasing number of people is a solution that may aggravate the problem of urban overcrowding, and the death of individuals is a problem that contributes to the solution of reducing ecological impact of overpopulation.