Summary form only given. The laser is a flexible machining tool which allows us to drill holes, to cut metals, to weld materials, and to make any kind of surface treatment without any contact to the workpiece itself. In the presentation examples of process monitoring and real-time process control are given. Considering industrial applications the process monitoring has to be integrated into the beam path to provide free access to the workpiece without blocking by diagnostic tools. New diagnostic devices as well as closed control loops to control the melt geometry depth the drilling, and the cutting process are demonstrated. The analysis of the laser induced plasma during the welding process and a control of the plasma absorption and plasma shielding are described and the closed control loop for laser welding of steel and aluminium is presented.