The Development of Meaning, by Joan Tough, is an investigation into children's use of language and its implications for their learning at home and at school. The study is essentially an enquiry into educational disadvantage. The basis of Dr Tough's research was a close study of the language used by selected groups of children from the age of three (when it would be known whether the child was to have nursery education or not). Because of the large quantities of data that would be produced, the maximum number of children included in the study was set at 64, 32 of whom had entered nursery schools and 32 who were not expected to do so. The children were seen again at five-and-a-half and seven-and-a-half.