We introduced this book reporting findings from the first three British birth cohort studies by considering the main features of 'half a century of change'. Since the end of the second world war, Britain has undergone a series of transformations, each of which impacted on the economic and social context in which our cohort members grew up. The 1944 Education Act, and the establishment of the National Health Service in 1948, provided the underpinnings of a welfare state, in which opportunities were to be available for all and the stultifying effects of poverty, so prevalent before the war, would finally be eliminated. These optimistic hopes supplied some of the foundations of later affluence, echoed in Harold Macmillan's famous phrase - "You've never had it so good".

But the path to sustained economic achievement and improved quality of life for all was never an easy one. Economic upswings were followed by economic downturns - "boom and bust" - and a growing belief that some of Britain's most longstanding institutions in the public and the private sector were inhibiting progress to the kind of world-class economy that technological transformation and globalisation were demanding. By the end of the 1970s, large areas of traditional industry were collapsing. The impact of the technological revolution that transformed employment in the 1970s and 1980s challenged fundamentally the social structures and institutions that had served Britain effectively in the past. Over the period covered by our cohorts, what had earlier been clear pathways to adult life dictated by gender, social class and local labour market prospects, were becoming increasingly blurred. The "job for life", which had been the aspiration and expectation of so many, disappeared, to be replaced by the much more fluid notion of a "portfolio career" in a labour market characterised by insecurity and uncertainty (Gershuny and Pahl 1994).

One consequence of the increasing risk and "individualisation" of life chances was the growing problem of alienation and social exclusion of some individuals and groups unwilling, or, more typically, unable, to take advantage of new opportunities. Social capital was in decline and social cohesion was under threat. Government attention therefore moved increasingly towards improving the life chances of marginalised groups.

The findings we have presented in this book need to be viewed against this backcloth of social, political and economic change. Different governments bring new policy scenarios, which form an important part of the context of people's lives. New solutions are offered for old problems and new policy is shaped in response to new problems as they emerge. In interpreting our results, we have drawn attention to the role of these contextual features as factors in some of the striking continuities and discontinuities across the era embraced by the studies that our analysis has revealed.

Our approach has been to compare the situations of our cohort members at comparable ages to establish cohort effects that might be attributed to socio-economic change impacting differentially on people born at different times. These need to be set against age differences reflecting the different changes between the stages of life. The time when follow-ups took place added the third factor accounting for differences, that to do with the prevailing socio-economic context at the time of data collection - the period effect. At each age and stage when comparisons have been made we have also drawn attention to differentiation identified with key demographic factors. We examine, particularly, evidence of differences identified with gender, social class of origin and destination, family structure and family economic status. Such differences lie at the heart of the differential life chances to which a major part of the scientific and policy research agenda using the birth cohort studies is directed.

We have been able to demonstrate societal trends by comparing the lives of our cohorts across the 24-year gap separating their births. The striking differences between their experiences, as manifested in their adult lives, can be attributed in large part to the effects of social change. But there are also continuities. The effects of such social structural factors as social class, gender, education and family background, though waning in some areas of life, are as strong as ever in others. Their effects on people's life chances interact with the effects of social change, as revealed by our findings. Our analysis enables us to see the extent to which these sources of disadvantage and opportunity continue to prevail.

Throughout the book there have been certain recurring themes, coalescing around our findings. They include:

· Continuities and discontinuities across cohorts associated with socio-economic change at different ages;

· The extension of the transition to adult life;

· Polarisation identified with gender, education, social class, family composition and economic position;

· The persistence of family social class as a driver of life chances;

· The growing importance of educational achievement and qualifications;

· Changes in the impact of gender;

· The growing role of risk, uncertainty and insecurity.

These feature strongly in the overview of findings that this chapter provides. We also set out some key elements of the research agenda that the cohort studies, enriched by the new data, enable us to address, and end by considering whether British lives are really changing and what this tells us about their likely shape in the new century.