  We predict the formation histories, properties and descendants of Lyman-break
galaxies (LBGs) in the Lambda-CDM cosmology. In our model, which incorporates a
top-heavy IMF in starbursts, we find that most LBGs are starbursts triggered by
minor mergers of galaxies. The duration of the LBG phase is predicted to be
quite short, ~20-60 Myr. We investigate the distributions of stellar and halo
masses and morphologies for bright (L_UV > L*_UV) and faint (L_UV > 0.1 L*_UV)
LBGs at z=3, z=6 and z=10 (where we classify LBGs according to their rest-frame
UV luminosities relative the observed characteristic luminosity L*_UV at z
\approx 3). Bright LBGs at z=3 are predicted to have median stellar masses ~
1x10^9 Msun/h and host halo masses ~ 3x10^{11} Msun/h, and to be typically
mildly disk-dominated in stellar mass. On the other hand, faint LBGs at z=10
are predicted to have median stellar masses of only ~ 1x10^7 Msun/h and host
halo masses 2x10^{10} Msun/h, and to be generally bulge-dominated. Bright LBGs
at z=3 evolve to present-day galaxies with median stellar mass ~ 5x^{10} Msun/h
(comparable to the Milky Way), consisting of roughly equal numbers of disk- and
bulge-dominated systems, and hosted by halos with median mass ~2x10^{13} Msun/h
(corresponding to medium-size galaxy groups). The model predicts that 40% of
Milky Way mass galaxies at the present-day have a bright LBG progenitor in the
redshift range 3<z<4, while 95% have a faint LBG progenitor in the same
redshift range, and 7% have a faint LBG progenitor at 10<z<11. With our
multiwavelength model, we also investigate the overlap between the LBG
population and that of submillimetre selected galaxies (SMGs); at z=3, only ~1%
of bright LBGs are also predicted to also be bright SMGs (with an 850 mum flux
in excess of 5 mJy).
