In a study of the general properties and evolution of galaxies it
is necessary to have quite a complete and representative sample
biased minimally by observational selection. A catalogue of all nearby
galaxies with distances 
would be an ideal realization of such
"fair" sample. To be representative such a sample must contain at least
(100-300) objects, which can be achieved at 
Mpc. The knowledge of
distances for all nearby galaxies permits both local dynamics
and the shape of the gravitational potential field to be evaluated.
Unfortunately, the distances remain one of the most deficient observing
parameters for the galaxies even in the vicinity of the Local Group.
Being short of distance data, Kraan-Korteweg & Tammann (1979) compiled
a catalogue of nearby galaxies with radial velocities V0 (corrected
for solar motion) not exceeding 
km/s. Their sample (=KKT) contains
179 galaxies (after excluding probable Virgo cluster members which
satisfy the condition V0 < 500 km/s due to large peculiar velocities). Then
Huchtmeier & Richter (1988, 1989a) and
Karachentsev (1994) increased the sample in the
number to N = 215 by including new objects detected in the HI 21 cm line by
different authors. Independent efforts to extend the KKT- sample were
undertaken by Schmidt & Boller (1992). However, their catalogue of 289 nearby
galaxies contains many questionable cases when the radial velocity refers to a
globular cluster or a star projected on a distant galaxy. Moreover, the
catalogue of Schmidt & Boller (1992) includes about 40 galaxies without
radial velocity, assuming their membership in the nearby groups, but later
HI observations did not confirm it.
The galaxy number distribution of the KKT- sample with radial velocities
as well as angular diameters show that its expected completeness is (
only. For instance, a median value of the linear diameter of the Local
Group galaxies equals 0.9 kpc (Karachentsev 1996). Being at D= 3.5 Mpc
(the distance of the nearest groups M 81 and Cent.A), a "median" dwarf
system has an angular diameter a=0.9 arcmin. In fact a lot of the faintest
objects in the KKT- sample are represented by the galaxies from the
catalogues: DDO
(van den Bergh 1966), UGC (Nilson 1973), and ESO/Uppsala
(Lauberts 1982) with a limiting angular diameter a=1 arcmin. So, we expect
that about (100-250) smaller galaxies really situated at D=4-6 Mpc have
not yet been covered by radial velocity surveys (and even have not yet been
discovered). The situation is complicated by the presence of the "Zone of
avoidance" because of the light extinction in the Milky Way plane.
As experience of the last two decades have shown, the increase in the number of the known galaxies with V0 < 500 km/s grows slowly (with a rate of 2-3 galaxies per year) and a discovery of very nearby galaxies happens in fact by chance. That is a reason for us to make special searches for the nearby dwarf galaxy candidates. We consider this work a part of a more extended program of studying the Local Volume galaxies (Karachentsev 1994).