Paul Stamets is not just an author. He is the formulator of the erstwhile New Chapter “Host Defense”.
When NC was bought, and the formula was changed, Stamets withdrew authorization, and started his own company in order to control quality.
Host Defense is now the name of the entire line. The former product by that name - now the flagship product - is called “MyCommunity”; it is a broad-spectrum blended formula instead of a targeted single mycomedicinal product.