In this chapter ``nearby'' is defined by the condition m - M < 31.2
(corresponding to 
< 17 Mpc and
<V> < 3000 km s-1). This condition
excludes the nearest large clusters of the Coma type and implies for
the brightest member galaxies an apparent magnitude
mG < 13
corresponding to the nominal limit of the Harvard census of 1250 galaxies
(Shapley and Ames 1932)
and to the estimated 50 percent
completeness level of the Reference Catalogue of Bright Galaxies
including twice as many galaxies
(G. and A. de
Vaucouleurs 1964).
In order to make the census of nearby groups as complete as possible, the following procedure was adopted:
1. A list was prepared of all galaxy groupings previously described in the literature as ``groups'' or ``clusters'' and which have at least one member in the Reference Catalogue.
2. A finding list of all possible pairs, multiple galaxies, or groups of bright galaxies was extracted from the Reference Catalogue by inspection of listings by coordinates and of distribution maps.
3. All recognized large clusters (Coma, Perseus, etc.) were rejected from further discussion.
4. A tabulation of galaxy types, magnitudes, diameters, and velocities was prepared for all other groupings which appeared likely to fall in the range defined above.
5. The relative distance moduli of the nearest groups (m - M < 30) were derived from all available secondary distance criteria (luminosity class, brightest stars, H II regions), using the distance moduli of the Local Group members derived from primary criteria (Cepheids, novae, RR Lyrae stars) for absolute calibration, on the distance scale defined by Sandage (1961) and by van den Bergh in chapter 12 of this volume.
6. Using the nearest groups as standards, tertiary distance indicators (luminosity and diameter) were calibrated as a function of galaxy type and rank and used to compute photometric and geometric moduli of all other identified groups and clusters.
This procedure appears to be successful for all groups including S and I systems, but the scarcity of nearby groups of E and L systems prevents a direct calibration of these classes by secondary criteria; the indirect calibration by means of groups including both S, I and E, L systems is somewhat uncertain because of the high degree of segregation (cf. Section 7.6).