By knowledge I (Richard R. Skemp) mean structured knowledge, not collections of isolated facts such as form the content of many television quiz shows. The practical importance of structured knowledge, as a foundation for relational understanding, was well put by a mature student at the Polytechnic of the South Bank, after a talk given there about relational and instrumental understanding. He said, 'Instrumental understanding, which is what I was given at school, only enabled me to deal with yesterday's technology. This is why I've had to come back to college and take evening classes, to get the relational understanding which will enable me to cope with the technology of the future.'