In Great Britain the output of limestone, sandstone, igneous rock and sand and gravel, most of which is used for aggregate, amounted to 256 million tonnes (Mt) in 1972, valued at about Pound 235 M (ex-pit). More aggregates are produced than any other mineral product, exceeding the coal output of 122 Mt (1972) by a substantial margin, although the value of the coal is substantially higher, Pound 847 M ex-pit. Since about half the average delivered price of aggregates may be attributable to transport charges, a significant part of the road transport industry can be grouped with the aggregate producers in an extraction-distribution complex with an output worth, perhaps, Pound 500 M a year. Although sized aggregates have been used in road making since the days of Telford and Macadam and 'as dug' gravel was used by the Romans, historically the quarrying industry was concerned largely with the supply of dimension stone for building and paving. However, with the increase in road construction following the development of the motor vehicle and the growth in the use of concrete in construction work, most of the stone is now crushed and used as aggregate, usually bound either with bituminous material or cement for dimensional stability. The industry has grown rapidly during the last 20 years and is expected to continue to grow in the future. However, the intrusion into the landscape, the noise, dust, and heavy traffic caused by the provision of aggregates to meet the demand for improvements in man's 'artificial' environment are in conflict with the increasing concern to protect his 'natural' environment. This paper indicates the technical, economic and geographical factors which affect this important industry and the properties, uses and resources of aggregates. It outlines the contribution that is being made by the Institute of Geological Sciences to improve knowledge of national resources.