In this talk, I will discuss correlation effects for a range of key processes in strong-field and attosecond physics. Electron-nuclear correlations will be discussed in connection with molecular breakup induced by strong low-frequency fields, and by intense high-frequency fields. Moreover effects of such correlations will be addressed in connection with attosecond transient absorption spectroscopy of molecules. Electron-electron correlations will be discussed in connection with the surprising emergence of low-energy electrons in strong-field ionization of molecules by circularly and close to circularly polarized fields. Finally efforts to develop tine-dependent wave functions based methods for the time-dependent many-electron problem will be mentioned.