ontology

Owl: Representing Information Using the Web Ontology Language
$39.95
The book met my expectations. Delivery was on time (as this was a desired factor for me)

Semantic Web for the Working Ontologist: Effective Modeling in RDFS and OWL
$49.95
The first few chapters do a good job of laying out the fundamental concepts of Semantic Web and RDF, gradually building you towards a complete understanding of this heady topic. I definitely recommend those chapters for people who want to get a solid grasp on RDF and the whole Semantic Web mentality.

From that intro, the book segues pretty smoothly into iteratively introducing layers of RDF's complexity & richness. If you're fond of (or at least unafraid of) formal logic, you will love the pragmatic way in which the authors lay out technical scenarios to make their point.

Truth and Ontology
$34.95
That there are no white ravens is true because there are no white ravens. And so there is a sense in which that truth "depends on the world." But this sort of dependence is trivial. After all, it does not imply that there is anything that is that truth's "truthmaker." Nor does it imply that something exists to which that truth corresponds. Nor does it imply that there are properties whose exemplification grounds that truth.
Trenton Merricks explores whether and how truth depends substantively on the world or on things or on being. And he takes a careful look at philosophical debates concerning, among other things, modality, time, and dispositions. He looks at these debates because any account of truth's substantive dependence on being has implications for them. And these debates likewise have implications for how and whether truth depends on being. Along the way, Merricks makes a number of new points about each of these debates that are of independent interest, of interest apart from the question of truth's dependence on being.
Truth and Ontology concludes that some truths do not depend on being in any substantive way at all. One result of this conclusion is that it is a mistake to oppose a philosophical theory merely because it violates truth's alleged substantive dependence on being. Another result is that the correspondence theory of truth is false and, more generally, that truth itself is not a relation of any sort between truth-bearers and that which "makes them true."

From an Ontological Point of View
$45.00
I agree with the other descriptions provided here. In addition, I would add that John Heil makes it clear where his expertise ends. He's not afraid to admit being confounded by claims made by other philosophers. This gives one a way forward in a field cluttered with contradictory claims.

It is actually helpful.

I would also point out that this book opens onto other work by the same author, written in the same clear style. I am currently enjoying the opportunity to explore his other books.

These are helpful, as well.