Reddit mentions of A Village to Village Guide to Hiking the Camino de Santiago, Camino Francés: St. Jean - Santiago - Finisterre

You'll love it! I'd listen to the other advice about trying to start a bit later to avoid big crowds as you near Santiago. Save 4 or 5 days after your arrival in Santiago to go on to Finisterra and chill there for a bit; I thought that was one of the most beautiful parts of the Camino, there are far fewer people, and the beaches are beautiful to relax on after a long month of walking.

I walked this year in August; I'd advise you to pack light and consider bringing only a sleeping bag liner instead of a sleeping bag. Maybe a swimsuit too, a few towns have beautiful public pools which are wonderful on a hot day.

You don't necessarily need a guide book, others will have them and will share and the way itself is very well marked. However, if you want a great one, I suggest this version: http://www.amazon.com/gp/aw/d/0984353348/ref=mp_s_a_1_3?qid=1394122278&sr=1-3

It had great info on basically every town, including where you'll find an ATM or pharmacy. Also interesting historical tidbits on the Camino itself. I brought it, and it quickly became the go-to guide for the group I met because of the useful stuff the authors thought to include.

Have a great walk! Buen Camino!