What is Shaffer-Landau attempting to do in his book, Whatever Happened to Good and Evil?

What is Shaffer-Landau attempting to do in his book, Whatever Happened to Good and Evil? What are his stances on Moral Skepticism and Ethical Objectivity? In answering this question, you must define and explain Meta-ethics and Ethical Objectivity; then define and discuss Moral Skepticism, and how each kind of skepticism rejects moral objectivity. Then discuss 3 of the named arguments (e.g. “Argument from Tolerance”) which he constructs on behalf of the moral skeptic, and what his analyses are (give the premises and conclusions and why he says the arguments are unsound). Discuss how the discussions of concepts of universal/objective/absolute and moral facts/moral principles help his case