Comprising a series of questionnaires completed by parents and children participating in the TEDS project, 1994-2003; including initial contact questionnaires completed when twins were approximately one year old containing the name of mother or father, address, telephone details, consent signatures, information on twins such as whether identical or non-identical, differences in appearance, sleep patterns, feeding issues, dress, siblings, pregnancy details with diet, the health of mother, any complications and overview of the circumstances of the birth, post-natal status, levels of stress in the home, relationship between parents and their education, occupations and background, 1995-1997 (IOP/TEDS 1); questionnaires for two year old children and their parents, comprising sets of three pamphlets of around 40 pages each, completed by the mother and each twin containing questions on changes in family circumstances since last interview, illness of twins, toilet habits, juvenile self awareness, sociability, behaviour patterns, emotional state, levels of play attainment with matching shapes, colours, brick-building, drawings and puzzles completed by the children themselves, 1996-1998 (IOP/TEDS 2); questionnaires of year three surveys comprising parents' and three year old twins' booklets and consisting of basic contact details similar to previous sections, more detailed examination of the twins' behaviour such as patience, levels of anxiety, propensity for self-harm, sociability, diet, play, speech patterns, songs, nursery rhymes, discipline, with drawings by the children and tests of their vocabulary, 1997-1999 (IOP/TEDS 3); questionnaires of year four surveys, with consent and contact information, changes in the health, diet, sleep patterns, play, discipline, communications, likes and dislikes, alterations in status of parents, with a greater focus on speech development, reading ability and puzzle solving capabilities of the children, with drawings, vocabulary and puzzle-solving tests completed by the children, 1998-2000 (IOP/TEDS 4); survey booklets for the siblings sub-project investigating the development of siblings in twins families, containing year two, three and four cohorts, and comprising a sample of the total TEDS volunteer families, focusing on the development of the sibling, play, discipline, sociability, home life, vocabulary and puzzle and picture tests completed by the children, 1997-2001 (IOP/TEDS 5); various questionnaires including semi-completed forms, those without consent signatures, forms not data-inputted, opt-outs from the programme, [1996-2000] (IOP/TEDS 6); papers relating to studies used in planning the TEDS project, including studies of hemiplegia, comprising questionnaires completed by parents of sufferers for the London Hemiplegia Register, consisting of data on the health and behaviour of child sufferers, 1988-1991, questionnaires completed by teachers for the MRC Child Psychiatry Unit, requesting insight into the behaviour of children mainly in Middlesex schools, with computer printouts of statistics of the project, 1995-1997, box of audio tapes relating to a Institute of Psychiatry project, [1988] (IOP/TEDS 7); TEDS Environment (E-Risk) project papers comprising questionnaires completed by researchers during interviews with mothers and children around the age of five, and with their teachers, and consisting of a range of questions and puzzles designed to examine in more detail the background of a sample group of about 1100 twins drawn from the main register, [1999-2003] (IOP/TEDS 8).