The usual questions: What is the book about? What do you want to say? What style are you in? Where/when's it set?

Why does it have to be free?

hhp

How About (TeX) Chorus? Downloadable lots of places, including here

http://www.1001fonts.com/tex-gyre-chorus-font.html

Ewww. The original was bad enough.

hhp

I take it you are looking for a fairly standard Roman letter, rather than Bible style blackletter or scripts. Anyway, you already have one script on the page. Something that looks reassuring without a lot of harsh threatening angles and that might even be seen as "inspirational."
If you really want to limit your choices to free, you might as well get something that's well made. A good prospect is Calluna by Jos Buivenga at exljbris. The regular weight is currently available free from Myfonts. http://www.myfonts.com/fonts/exljbris/calluna/
BTW white on black for this topic suggests a funeral. Why not something in a cheerful pastel?
Don