Time-resolved high-harmonic spectroscopy of valence electron dynamics

► We discuss the principles of time-resolved high-harmonic spectroscopy (TRHHS). ► We analyze its sensitivity to nuclear and electronic dynamics of molecules. ► We establish the link between wave packet dynamics and the observables of TRHHS. ► In mainly 1D dynamics, TRHHS measures the Ip and the recombination dipoles. ► In multidimensional dynamics, TRHHS is sensitive to electronic population dynamics.