A digital reconstruction of a prototypical neocortical microcircuit is presented. A novel strategy enabled a first draft of a full reconstruction from partial anatomical and physiological data on the cellular and synaptic organization of the somatosensory cortex of a two-week old rat. This first draft cellular-level map of the microcircuit predicts the number of neurones of each morphological and electrical type per layer (the neurome), all intrinsic and extrinsic synaptic connections involved (the connectome), and complete maps of intrinsic synapses for each neurones (the synaptomes). In silico simulations revealed a robust activity spectrum, ranging from synchrony to asynchrony (SA spectrum). Modulating synapses, neurones and layers shift the network along the spectrum and changes network properties. The digital reconstruction of the neocortical microcircuit is being made freely available for independent investigation and to facilitate collaborative refinement of the predictions.