1. The history of matrix isolation spectroscopy..- Section A - Techniques.- 2. Infrared and Raman matrix isolation spectroscopy..- 3. Electronic spectroscopy of matrix isolated solutes..- 4. Magnetic circular dichroism - matrix isolation spectroscopy..- 5. Electron spin resonance studies of radicals trapped in rare-gas matrices..- 6. Mössbauer spectroscopy on matrix-isolated species.- 7. Time and frequency resolved vibrational spectroscopy of matrix isolated molecules: Population and phase relaxation processes..- 8. Stable molecules..- 9. Generation and trapping of unstable solutes in low temperature matrices..- 10. The characterisation of high temperature molecules using matrix isolation and vibrational spectroscopy..- 11. High pressure studies..- 12. Non-traditional matrix isolation: adducts..- Section B - Matrix Effects.- 13. Interpretation of infrared and Raman spectra of trapped molecular impurities from interaction potential calculations..- 14. Matrix induced changes in the electronic spectra of isolated atoms and molecules..- 15. Matrix effects studied by electron spin resonance spectroscopy..- 16. Molecular motion in matrices..- 17. Vibrational band intensities in matrices..- Section C - Applications.- 18. Matrix isolation spectroscopy of metal atoms and small clusters..- 19. Vibrational spectra of matrix isolated gaseous ternary oxides..- 20. Matrix isolation spectra (IR, Raman) of transition metal compounds..- 21. Metal carbonyls - structure, photochemistry, and IR lasers..- 22. Matrix isolation vibrational spectroscopy on organic molecules..- 23. Conformational isomerism studied by matrix isolation vibrational spectroscopy..- 24. Hydrogen bonding in matrices..- Author Index.