Given the myriad of studies on glutamate receptors and synaptic transmission in recent years, it's hard to believe that little more than 20 years have elapsed since the first description of synaptic N-methyl-d-aspartate (NMDA) ionotropic glutamate receptors. Whereas today we readily accept the dual nature of excitatory postsynaptic currents comprised of rapidly activating and deactivating AMPA receptors together with slowly rising and decaying NMDA receptor responses, this advance in our understanding did not come easy. Rather, like many scientific discoveries that appear obvious in hindsight, this observation required a great deal of careful work by a number of thoughtful investigators over the course of ∼6 years. Here we review two particularly important papers within this body of work that brought our understanding of excitatory synaptic transmission and its role in hyperexcitability to where it is today: centre stage in virtually every central synapse.