To unterstand good and evil, would it not be prudent to understand death first ?

Who says we can't understand death? Death is the cessation of life. Death is sometimes the result of evil acts, but not always. Sometimes death is completely natural. An exploding volcano could kill thousands of people, but it isn't evil - evil is a human quality that requires deliberate malice. I don't think I need evil to understand good either. I think I can recognize good for itself. Evil makes me appreciate good all the more, but I don't think its necessary to recognize the good.