Mariette Effing (NL) has been the conductor of the City Boys’ Choir Oldenzaal in the Netherlands since 1998. In that position, she has gained valuable experience in working with boys and young men of different ages. For the one 100th anniversary of the City Boys’ Choir Oldenzaal in 2015, she organised Boys, keep on singing! In that project, she focused on singing with boys and especially on how to ensure their continued interest in singing. Everywhere around her, both in her own country and internationally, Mariette sees a reduction in the proportion of boys and men singing. This trend inspired her to organise a symposium and a boys’ choir festival in 2015. It enabled not only several boys’ choirs to meet, but also specialists and professionals working with boys’ voices, such as conductors, singing teachers and teachers in primary and secondary schools. It was especially for this project that she compiled the songbook Boys, keep on singing!, full of existing and new compositions for boys’ and young men’s voices only. The focus of this songbook is on the development of boys’ choirs and boys’ voices, using repertoire specifically for boys of different age groups and levels. Mariette Effing studied school music and choral conducting. Apart from her work as a conductor, she is a member of the editorial committee of specialist journal ZINGmagazine.