  We present the results of observations of the galaxy Holmberg I carried out
at the Russian 6-m telescope in the narrow-band imaging, long-slit
spectroscopy, and scanning Fabry-Perot interferometer modes. A detailed
analysis of gas kinematics, ionization conditions, and metallicity of
star-forming regions in the galaxy is presented. The aim of the paper is to
analyse the propagation of star formation in the galaxy and to understand the
role of the ongoing star formation in the evolution of the central
'galaxy-sized' supergiant HI shell (SGS), where all regions of star formation
are observed. We show that star formation in the galaxy occurs in large unified
complexes rather than in individual giant HII regions. Evidence of the
triggered star formation is observed both on scales of individual complexes and
of the whole galaxy. We identified two supernova-remnant candidates and one
late-type WN star and analysed their spectrum and surrounding-gas kinematics.
We provide arguments indicating that the SGS in Holmberg I is destructing by
the influence of star formation occurring on its rims.
