The Dutch hornist Ab Koster was professor of horn at the Hochschule für Musik und Theater in Hamburg for 39 years, retiring in 2019; 94% of his former students hold positions as professional performers. Ab is also known as an outstanding orchestral player and as soloist on both natural and modern horn. He has been active in the IHS as a featured artist at IHS symposiums and serving on the Advisory Council for two terms (1998-2001 and 2014-2016).

Ab was born in The Hague, Holland, the son of a Dutch hornist. He completed his studies at the Royal Conservatory of Music in his hometown with a Prix d’Exellence, then continued at the Folkwang University in Essen, Germany with Hermann Baumann, who called him one of the “leading hornist of his generation.”

Ab held the position of principal horn in the NDR Symphony Orchestra in Hamburg, Germany from 1977 until 1990, when he left in order to accept many invitations as soloist and chamber musician. He has  collaborated with Jean-Pierre Rampal, Gustav Leonhardt, and Frans Brüggen (Orchestra of the 18th Century) and earned an international reputation with solo performances, records, radio, and television recordings in various countries. Concert tours have led him to almost all countries in Europe as well as in the US, Canada, Japan, Australia, China, and Taiwan.

For years, Ab has belonged to the small circle of soloists who are sought after world-wide, on the natural horn as well as on the valve horn. His interpretation of the concertos by Mozart and Strauss are particularly celebrated all over the world.