The origins of the “object concept” is one the oldest and most central questions in the study of cognitive development. Traditional accounts assume that objects emerge from the association of sensory features to form bundles that are stored in long term memory and used in recognition. Piaget introduced us to the ubiquitous problem of persistence in the 3-D world of the infant. A sea-change in our view of infant cognition took place in the 1980’s through the work of Spelke, Baillargeon, and others who introduced us to the object principles and infant physical reasoning. Slightly more recently, Scholl and I, together with the Carey group, forged links between infant object cognition and ideas drawn from the study of object based attention in adults. This work introduced object indexing, a mechanism of object-based attention, and the object file, a data structure, combining a ‘sticky’ index with feature binding. It also provided a framework for understanding how infants can attend to multiple objects simultaneously, a discovery that Wynn had made a few years before. This talk will summarize work from my lab and others documenting how infants in the first year bind sensory features to multiple object indexes in working memory (WM). Indexing and WM are both thought of as “intermediate level” mechanisms of object cognition, and WM as where the bottom-up and the top-down come together. Whereas limits on indexing are established early in the first year and don’t change thereafter, limits on feature binding are a severe one object at 6 months and grow to two and then to three objects by 12 months. I end with the notion of “concept binding”.