Introduction : longitudinal perspectives on the income distribution -- Measurement and data. Income over time : measurement issues ; Sources of longitudinal data on income : household panel surveys in context ; The British household panel survey and its income data -- Income mobility. Income mobility and how it has changed over time ; Transitory variation and volatility in income ; Spaghetti unravelled : a model-based description of differences in income-age trajectories -- Poverty dynamics. Poverty dynamics and how they have changed over time ; Routes into and out of poverty and the role of trigger events ; The length of time spent poor : estimates from hazard regression models ; Modelling low income transitions : estimates from a Markov model -- Envoi. Summary and conclusions.