Greetje Mastromichalis keeps the business side running smoothly and assists clients and guests who visit Polyhymnia. After finishing her M.E.A.O. in 1981 Greetje worked at various organizations, including Howson-Alprahy, Nationale Woningraad, N.C.R.V. and Polygram. In 1988 she came to work at the Philips Classics Recording Centre (precursor to Polyhymnia) as an assistant to the recording department manager. Greetje has been the office manager of Polyhymnia since its inception in 1998.