Flashman
by George MacDonald Fraser
The villain of Tom Brown's Schooldays (and so the original Malfoy), having been sent home for getting drunk, gets an unexpectedly early start on adult life. He's a thoroughgoing scoundrel, as he himself will be the first to tell you, and so he goes from strength to strength. On rare occasions, he has a moment of weakness and does a good thing, and for these failures the moral universe punishes him severely, but character and his intrinsic terribleness win out in the end. The first in a long, literate series.