The period established the nucleosome as the fundamental repeating unit of chromatin, integrating biochemical, imaging, and cytogenetic evidence to explain DNA packaging and accessibility. The approach combined crosslinking, electron microscopy, and histone–DNA interaction studies to propose a coherent architecture for chromatin and its dynamic regulation. Historical Significance: These findings unified structural biology with gene regulation concepts, setting the stage for later exploration of higher‑order chromatin organization and the epigenetic paradigm, while underscoring the central role of histones in genome function.