Emma Maleras created a method that approached castanets like any other instrument: with respect and rigour. She created the bigram, and her pianistic background proved to be priceless. She dignified the instrument and made it achieve soloistic category.
I did not get to know her, but I did buy and study her books. Thanks to them I left my ignorance behind, and my perception of the instrument changed for ever. I am far (very far) from being a castanet vistuoso, but I am on my way to being able to play castanets at least as well as I play other instruments.
If you are interested in playing castanets the proper way, I encourage you to get her
METHOD (check all the volumes).
May she rest in peace.