After a three year stint at the National Radio Astronomy Observatory in the sixties, where the basis for the book was already laid, he participated in the design, construction, commissioning and operation of the Westerbork Synthesis Radio Telescope. Upon moving to the Max-Planck-Institut für Radioastronomie in Bonn in 1975, Baars was project manager for two highly successful millimeter wave radio telescopes – the IRAM mm-telescope on Pico Veleta, Spain and the Heinrich Hertz Telescope on Mt. Graham, Arizona, USA. Since 1999. He has been with the European Southern Observatory in Garching, participating with different tasks in the ALMA Project, in particular the evaluation of two prototype submillimeter radio telescopes.