What necromancy is and isn't.
Necromancy is communication, evocation, interaction, and divination with spirits of the dead. It's roots lie in ancestor worship and funerary rites and every culture has it's own ways. The oldest form of necromancy was practiced by the medicine people and shamans of tribes. Greek and Egyptian practices influenced modern ceremonial magick methods.
Necromancy is not the manipulation of "death energy" like the video games. In fact, it has nothing to do with that at all. Anyone that works with the lower worlds understands that death is not a state of being but a passage from one existence to the next. You do not need to wear all black, you won't become pale, and you definitely don't need to hang out in cemeteries.
Eliphas Levi was a famous CM necromancer and he wrote many books.
I recommend Transcendental Magic. It is not a beginner's book. It is dense and read like a real magick book should, not the watered down info in modern literature.
If you have no experience in magick, than I suggest you hold off on necromancy and ceremonial magick. Learn the basics of magick itself first. Many people have good things to say about Modern Magic by Kraig.