Understanding Society: the UK Household Longitudinal Study is the largest household panel study in the world, designed to address key scientific and policy questions of the 21st century. It collects high quality annual longitudinal data on individuals of all ages in households which are representative of the UK population. The Study's data enable researchers to explore the experiences, causes and consequences of changes in people's lives - their family structure, health, income, expenditure, employment and housing. The Study has additional dimensions that enable the detailed exploration of the circumstances of key immigrant and ethnic minority groups; investigation of inter-relations between different family members within and across households and generations; and, it collects direct measures of health and genetics to understand how people's health and wider circumstances interact. It is underpinned by robust and innovative methods, and our methodological research creates learning for other studies nationally and internationally. The Study began in 2008 with the Innovation Panel (IP), which tests methods, and the first main wave of fieldwork started in 2009. It builds on and incorporates the British Household Panel Survey, which means for some families we have data from 1991. To date, eight waves of the main Study and ten waves of the IP, as well as data collected from a nurse visit, are deposited at the UK Data Service. Further waves are in planning, in the field or being prepared for data release. This bid covers plans for data collection for Waves 13-15 and IP15-17 a boost sample to increase the size of the Study, and a range of enhancements. Our long term vision for the Study is for it to be based on integrating the best of all kinds of data on a Longitudinal Core, whilst creating novel research opportunities with new data enhancements. Our plans include more timely data collection of key life changes, such as job loss; a pregnancy study; a repeat collection of biological data. We are investigating ways to enhance our content by collecting data with new technologies. We are also planning to expand the Study to engage with key family members who live outside the household, for example, co-parents in separated families and transnational families. We also plan to broaden the range of data we harvest from external sources, as well as individual administrative records, we are investigating how we can obtain contextual data on organisations, such as employers, and places. As in previous bids, we are proposing advertising a number of fellowships competitions to build capacity in the wider research community to use the unique features of the data. Supporting researchers in universities, government, third sector and businesses to use the data effectively is fundamental to the success of the Study. We provide a wide range of resources, services and support to enable users with different backgrounds and from different kinds of organisations to make effective use of the data. We propose enhancing this further by adding a 'data gateway' to our website so users can select the data they need through a shopping basket system. We have a Policy Unit that works directly with government departments and third sector organisations to help them use Understanding Society data, and we undertake a wide range of activities to promote findings based on the Study to policy users. In this phase the Policy Unit will develop partnerships with different organisations to facilitate policy communities learning from high quality research based on the Study. We plan to continue to promote research from the Study widely through events, publications, briefings, on our website and through social media. Taken together, we firmly believe that the continued collection of data on a longitudinal core and the new data enhancements proposed will significantly increase the high quality impactful research based on the Study and hence its value to society.