How do young people in Switzerland find their way into and through post-compulsory education and, later on, into professional and adult life? How do they fare on their pathways? Which plans, dreams and aspirations do they have? What difficulties do they encounter along the way? These are some of the central questions at the heart of the TREE study (Transitions from Education to Employment). TREE is a large panel survey following up compulsory school leavers from all over Switzerland through their post-compulsory education and training and into employment and adulthood. The first TREE cohort (TREE1) started in 2000 and has been interviewed nine times to date. The second TREE cohort (TREE2) left compulsory school in 2016. The TREE study is mainly funded be the Swiss National Science Foundation.