One of the most common models of neural computation makes use of neural assemblies – an ensemble of neurons that are coactivated and jointly perform a certain function. This simple concept has far-reaching consequences in how we may understand the brain. This talk will begin with a survey of the concept of neural assemblies, and then spend some time on recent technologies that have been developed to study assembly circuitry. Specifically, I will discuss advances made in specifically labelling and manipulating neurons within an ensemble in both slice and in vivo preparations. Will we be able to find the mysterious engram? Stay tuned to find out!