Warehouses have always been an essential part of supply chains, but despite their fundamental role they were not seen as especially mission critical. With the advent of e-commerce, same-day deliveries, omni-channel retailing, and global supply chain disruptions, however, this assessment has changed, and today’s warehouses have evolved to technology-enriched fulfillment factories with strategic relevance. This paper traces the evolution of picker-to-parts and parts-to-picker warehouses from basic systems of the first generation, via extended system setups of the second generation, up to state-of-the-art robotized distribution centers of the third generation. Specifically, we highlight the most influential scientific contributions of the operations research (OR) community within each generation that have supported this evolution over the past 50 years. Beyond the historical perspective, we outline an agenda for the warehousing research of the future. •We structure the evolution of warehousing systems into three generations.•We survey most influential research contributions for each generation.•A research agenda for future warehousing generations is outlined.