The mythology of the ancient Finns and its sources; Iron Age society and its gods; Ukko and other euphemisms for the God of Thunder; Rauni; Ukko behind his euphemism; Ilmari, the God of the Winds; Ilmarinen, forger god and heroic smith; Ukko and shooting the fire; By Hieros gamos; The testimony of the elliptical fire stones; Ukko¿s cloak; Thunderbolts; Ukko¿s wedge, nail, fingernail, arrow, and chisel; Foreign thunderbolts; Ukko¿s sword; Ukko¿s hammer, ax, and club; The Thunder God and Mother Goddess; The Battle Axe Culture and the God of Thunder; Tapering-headed battle axes and the God of Thunder; Ukko in the skies of the lake region?; The evidence of the Late Neolithic shaft-hole axes; The Bronze Age shaft-hole axes; Historical-linguistic viewpoints; The Bird God; Ukko¿s long history: Conclusions, arguments, assumptions; Abbreviations; plus Eighty Illustrations