Just in time (JIT) is a production strategy that aims to reduce inventory and associated costs by producing and delivering goods only as needed. Key aspects of JIT include using signals between production steps to trigger making the next part, implementing kanban systems, continuous improvement, and focusing on quality, flow, and employee involvement. JIT requires accurate forecasting and reliable suppliers to minimize inventory while meeting production needs. Implemented correctly, JIT can improve return on investment, quality, and efficiency for manufacturers.