While the importance of the immune synapse as a dynamic cell junction that regulates intercellular communication and viral transmission is universally recognized, many of quantitative and qualitative details remain unsettled. The plasticity of this cell junction has to accommodate many very different binding partners and control the fate of interacting cells. It is likely that developmental changes in the state of the T cells or the APCs can impact the structure of the synapse. It is hoped that uncovering the ordered molecular rearrangement at the membrane will provide the long sought after clues for the remarkable functional sensitivity of T lymphocytes. These dynamic molecular interactions may eventually explain how engagement of the same TCR can generate different outcomes that resolve the immune challenges. The reviews in this issue present a broad slice of the many diverse topics that are currently intensely debated.