Three principal categories of giant galaxies are defined in terms of their stellar population: (1) the Orion category (some irregulars), rich in H ii regions, giant blue stars, and a high gas density; (2) the Intermediate (giant spirals similar to NGC 5194 and 4321), absorption spectral types of class F, together with a high degree of compositeness; (3) the Amorphous (nuclear regions of centrally condensed spirals like M3 1, and the entire main bodies of the giant ellipticals), spectral types near KO in the blue and violet regions-to- gether with giant spectroscopic characteristics. A category of "Combination Galaxies" is defined in terms of a marked difference between the absorption spectral type of the nuclear region and the main body. The Androrneda Galaxy is a prototype for this group. It is shown that our own Galaxy also belongs to this "Corn- bination" category. It seems probable that the spectrum of the peculiar irregular NGC 5195 is of the weak- lined variety. In Sec. XI a review is given of the behavior of emission lines in ordinary galaxies, Seyfert galaxies, and strong radio sources.