What is a CNS? Well, the other advanced practice nurses are fairly easy to understand - but this book says it all. It has been the most used book (okay, well, besides my Rosen's for emergency care) I own. Dr. Hamric is very well respected and known and the respective authors in the book are nationally known and respected. This is THE book and highly recommended for anyone wanting to know about advanced practice nursing, where we came from, the theory behind what we do and why, issues that are facing us and outcomes and more and more. I've used it for EVERY core content class and see myself using it even when I'm practicing. I'm glad that our CNS professor had us purchase this book over any other role book. It really is an excellent resource.