For that you want to look into the old grimores and books on witchcraft. The older and more ancient the better. For egyptian/greek magick, you would look for the magical papyri. Budge has a few free ebooks on egyptian ritual work and religion. He's a little outdated and some of his translations are not entirely accurate, but you'll get a taste of what old magick consisted of. There is quite a lot of old grimoires of kabbalist (hebrew) magick, including the well know Greater and Lesser Keys of Solomon. I also always recommend Agrippa. I think he's a fantastic author but he speaks more on the internal mechanics of magick more so than actual rituals/spells. The Sixth and Seventh Books of Moses I find interesting. I've read through some of them. Crowley although insane was a genius and as long as you read his work with a analytical mind, you'll gain a lot of insight. He also rewrote many ancient rituals to fit his own style, such as the well know Lesser Banishing Ritual of the Pentagram.
It really all depends on what direction you plan to take. There are many, but I always suggest reading the ancient stuff to understand the difference between "neo" or "new age" magick and the *cough* real stuff. =)
There are a very rare few modern books I will ever recommend. In my opinion, most of it is garbage and will only shape you into a fluffy bunny.