I have no idea if the site posting this actually has the copyright permissions to do this or not, but there is a site with the entire copy of Walter Sinnott-Armstrong’s book, Moral Skepticisms, available as a PDF file.

For those of you with an interest in learning more about metaethics–such as the distinction between “moral metaphysics” (moral ontology), “moral linguistics” (moral semantics), and so forth, check out pages 5-7 of the PDF file, especially the diagram on page 6.