In summary, despite the frantic increase in publication rate in this field, there is an enormous amount of work still to be done, both observationally, in exploiting the connection between resolved images from HST and ground-based spectroscopy, and theoretically, in predicting more accurately the expected evolutionary histories of resolved components. In my opinion the subject suffers too much from a satisfaction with simply replicating, according to a particular theory, a range of observations. This is particularly dangerous when the observables are luminosities, colors and star formation rates since the theoretical parameters involved are numerous. The challenge will be to overcome the obvious limitations we presently face in determining galactic masses for complete samples of galaxies viewed at various look-back times, as well as integrating the growing body of data being obtained in the far infrared and sub-mm spectral regions.
I thank my students, past and present, and collaborators at Cambridge, Caltech and elsewhere for allowing me to present the results of unpublished work undertaken with them. I also thank Marc Balcells, Ismael Perez-Fournon and Francisco Sanchez for inviting me to Tenerife to give these lectures and for their remarkable patience in waiting for this written version.