This document discusses process analytical technology (PAT) and various techniques used for monitoring biopharmaceutical manufacturing processes. PAT aims to design, analyze, and control processes through measuring critical process parameters and quality attributes. Several spectroscopic techniques are described that can be used for in-line monitoring of processes, including UV-vis spectroscopy, FTIR, NIR, NMR, Raman spectroscopy, and DLS. Control strategies like open-loop, closed-loop, cascade, neural network-based and model-based controls are summarized. Bioprocess control and automation are important for continuous monitoring and production of biotherapeutics.