is even more challenging, given the problems of gathering data about children, and given the multiple and changing influences and decision-makers in their lives in the span from infancy to adolescence. That is where the Scientific Platform project of the EU Working Party on Information on Lifestyle and Special Population groups comes into effect. Its task in the year 2007 has been to ascertain the availability of data at national level in EU Member State, Applicant State, and European Economic Area nations. And to enable that work to be undertaken, a baseline analysis of the aspects to be measured in terms of lifestyle determinants was undertaken on behalf of the project partners by the Centre for Health Planning and Management, Keele University. This publication seeks to share that knowledge and current evidence on measurement issues in childhood obesity determinants for a wider readership. TOC:Volume 1: 1. Overview of the Child Obesity and Overweight Epidemic.- 2. Challenges of Gathering Behavioural Data about Children.- 3. Measuring Behaviour and Nutrition of Infants and Young Children (Infancy-9 years).- 4. Measuring Behaviour and Nutrition of Older Children and Adolescents (Aged 10-17 years).- 5. Measuring Physical Activity of Young Children (Infancy-9 years).- 6. Measuring Physical Activity of School Children (Aged 10-14 years).- 7. Measuring Physical Activity of Adolescents (Aged 15-17 years).- 8. Data-gathering Initiatives of International Organisations.- 9. Behaviour and Eating Disorders.- 10. The Behavioural Influence of Advertising, Marketing and Labelling.- 11. Conclusions.