We study the kinetic regime of the Bose condensation of scalar particl
es. The Boltzmann equation is solved numerically. We consider two kine
tic stages. At the first stage the condensate is absent but there is a
nonzero inflow of particles towards p=0 and the distribution function
at p=0 grows from finite values to infinity in a finite time. We obse
rve a profound similarity between Bose condensation and Kolmogorov tur
bulence. At the second stage there are two components, the condensate
and particles, reaching their equilibrium values. We show that the evo
lution in both stages proceeds in a self-similar way and find the time
needed for condensation. We do not consider a phase transition from t
he first stage to the second. Condensation of self-interacting bosons
is compared to the condensation driven by interaction with a cold gas
of fermions; the latter turns out to be self-similar too. Exploiting t
he self-similarity we obtain a number of analytical results in all cas
es.