The Danish soprano, Ruth Guldbaek, began her training in the singing class of the Folke Theatre in Copenhagen; was from 1942 to 1944 as Elevin at the Copenhagen New Theatre and from 1944 to 1947 at the Opera School of the Royal Opera in Copenhagen.
Ruth Guldbaek made her stage debut in at the Copenhagen Opera as Zerline in Don Giovanni. Since then she had important career at this opera house for many years. In 1950 she resumed studies with Edytha Fleischer in Vienna, then with Maria Labia in Milan. In 1951-1952 she appeared as a guest at the Covent Garden Opera in London as Sophie in the Rosenkavalier, and in 1954 as Susanna in Nozze di Figaro. She preferred to sing on stage roles of soubrette and coloratura as Ännchen in Freischütz, Musetta in La Bohème and Fiordiligi in Così fan tutte. She had no less important career in the concert hall, above all as an interpreter of oratorios and sacred vocal works.
Recordings: HMV (Bach Cantatas), Danacorn (Mikal in Saul og David by C. Nielsen, 1960), CBS (Symphony of C. Nielsen).