Hans Bloemendal was the cantor or hazzan of the synagogue in Amsterdam. Don’t be confused if you’re trying to find him on google: yes, he was also a prominent biochemist and had a resounding career in both worlds. So much for specialising!
His parents and his only sister were murdered in Sobibor in the Second World War, with Hans escaping the cruel fate by hiding and finding refuge with a catholic family in Alphen aan de Rijn. After the war he found himself singing at a Jewish old peoples home in the centre of Amsterdam. When there was an open position as cantor in a nearby synagogue, the elderly people put him forward. With some lessons and hard work, he managed to get the aforementioned position of hazzan.
As such, he released many recordings, wrote books on the subject, and collected what is still considered a standard collection of songs for the job. And all that, while also having a university career in Nijmegen and doing research into protein structures of eye lenses.