My favorite name book - just a little paperback picked up used when I was 14. I read it over and over. I was fascinated by names and what they meant and all the nicknames one could make out of those names.
I learned, for instance, Neysa is a nickname for Agnes. Neysa is such a pretty name. If I ever wrote a book, she'd be my leading character. Her middle name would be Elizabeth. (I had all this decided when I was 14 and it would be sacrilege to change it now. Not that I'm actually writing a book, but if I do - watch out! Neysa E will save the day.)