One of the main objectives of the European Community Programme on Solar Energy is to provide solar energy practitioners -- architects and engineers who design and implement both active and passive solar energy systems, including biomass and daylighting systems -- with well documented meteorological and climatological data so that they can estimate the solar radiation falling on a receiving surface for any location and at any time throughout the year. As a complement to its other landmark contributions in providing firm data to the solar energy community, the CEC launched a new, 36-month-long programme on 1 April 1986, which was intended to provide a better understanding of the relationship between climatic factors and solar radiation, determine the effect of anthropogenic pollution on the amount of usable solar energy, and establish sound models for the correlation between weather data, pollution, regional orography, coastal influence and the solar radiation pattern. The current volume presents the results of this research programme, gathered from eight characteristic sites in the EC. The first three chapters deal with the problem in general, present the environmental parameters which influence the radiation climate of a site, and explain the process of modelling microclimate solar radiation for a specific site. Chapter 4 deals with specific methods for evaluating microclimate solar radiation, using both a software package and a pocket calculator. Chapter 5 supplies extensive references.