There are few things more satisfying to enviers than the demise or expense of their targets. If you can't have it, whatever it is, all the more better that they should suffer humiliation and misery; a trademark of envy, according to the author, known as "Schadenfreude". In this book, the author looks at envy in nearly all of its incarnations, ranging from envy of the youth, envy of beauty, envy of the Jews, and makes an unusual case in pointing out that societies designed to purge envy from the people instead create more envy within (a bit hard to follow for me, personally). He provides tips on "Spotting the Envious" people, and also helps better define "envy" from its related forms, such as resentment, ressentiment, and jealousy. He says while jealousy involves matters of the heart, envy involves matters of other's possessions; jealousy, despite popular thought, is not envy.
Of all the books I've read in the Seven Sins series so far, this has provided the easiest read. It's easy to follow, and the author makes his points with a humorous edge, and without delving too much into inner psychiatry or politics.