There are basically two kinds of intro philosophy texts: General intros and anthologies of "classic" papers. As Andrew mentioned in his reply to your question, a search on amazon.com will turn up many good anthologies. But the two general intros that I heartily recommend are: Nagel, Thomas (1987), What Does It All Mean? A Very Short Introduction to Philosophy (Oxford: Oxford University Press) and an "oldie but goodie": Russell, Bertrand (1912), The Problems of Philosophy , various editions and publishers

My favorite for beginners (although the author is somewhat out of favor with some professional philosophers these days) is Thomas Nagel's What Does It All Mean?: A Very Short Introduction to Philosophy . It raises all of the interesting questions in a readable fashion, but leaves the answers to the reader. (And the author of The Story of Philosophy , by the way, spelled his name "Will Durant".)

I don't know what you mean by "ontology", which can refer to either the branch of philosophy (metaphysics) that is concerned with existence or the branch of artificial intelligence that is concerned with knowledge representation techniques for organizing information (both of those characterizations are very, very rough, of course). In the latter case, you might want to look into doctoral programs in either philosophy or computer science departments where there are researchers specializing in that, such as the (SUNY) Buffalo Center for Ontological Research (disclaimer: that's my institution!). For more information on this kind of ontology, see http://aitopics.net/Ontologies

Here are two suggestions. The first is less of a philosophy blog and more of a metaphilosophy blog, but it often has useful links to other blogs that you might like: "Leiter Reports: A Philosophy Blog / News and views about philosophy, the academic profession, academic freedom, intellectual culture...and a bit of poetry" http://leiterreports.typepad.com/ The second is also not quite a philosophy blog itself but a philosophy metablog, with summaries and pointers to other philosophy blogs: "Philosopher's Carnival" Its location seems to move around and is always posted on the Leiter Report. The current version is at: http://ichthus77.blogspot.com/2012/02/philosophers-carnival-138.html

There are 2 ways to interpret your question. One way is as a request for information about the philosophy of engineering. If that's what you're asking, I can suggest two good books to start with: Florman, Samuel C. (1994), The Existential Pleasures of Engineering, 2nd edition (New York: St. Martin's Press). Davis, Michael (1998), Thinking Like an Engineer: Studies in the Ethics of a Profession (New York: Oxford University Press). The first was written by a practicing engineer, the second by a philosopher. Both deal with questions like: What is engineering? How should engineers behave? You might find some other references on the webpage "What Is Engineering?" for my Philosophy of Computer Science course . There is also a branch of philosophy called the philosophy of technology, which deals with related issues. Check the article with that title in the Stanford Encyclopedia of Philosophy. The other interpretation is as a request for information about how to apply...

Another alternative is to read Kant's very own "Cliff's Notes" version of the Critique, namely, his Prolegomena to Any Future Metaphysics. Again, there are numerous inexpensive editions, or go to your local library; it's also online at http://www.mnstate.edu/gracyk/courses/phil%20306/kant_materials/prolegomena1.htm (and probably elsewhere). It's much shorter than the Critique, and much more readable. And well worth reading!

I agree with Allen Stairs that reading topically is important, but I think it is equally important to remember that philosophy is a conversation that has been ongoing for something like 4500 years. To join in on the conversation, it can be very useful to see it historically , to see how it began and how it evolved, and thereby to gain an understanding of why it is where it is today. One can combine these approaches: Read chronologically within a topic. Or read contemporary philosophy alongside its history. To compare philosophy with physics, as Stairs does, misleadingly suggests that the history is irrelevant. (That's not to say that philosophy doesn't "make progress"; on that topic, see my essay: Rapaport, William J. (1982), "Unsolvable Problems and Philosophical Progress" , American Philosophical Quarterly 19: 289-298.)

Robert Audi's Cambridge Dictionary of Philosophy is another excellent one. But I dislike dictionaries, especially for philosophy, where proper explication of terms requires a bit more discussion than most brief dictionary entries allow for. So after reading a definition in either the Cambridge or the Oxford dictionaries, I strongly advise you to read more about whatever term you were looking up by linking to the excellent, on-line Stanford Encyclopedia of Philosophy on the right-hand side of the askphilosophers.org website (or google it, or click on the title in this response).

If by "current", you really mean "very latest", then one way is to keepup to date with the major journals in those topics. For a (partial)list, take a look at one of the webpages for my Intro to CognitiveScience course, " Sources of Information on Cognitive Science ". Depending on what kind ofaccess you have to a university library and its electronic journalofferings, you can also often subscribe to online table-of-contentsalerts for many journals. If by "current", you meant something more like "classic problemsthat are currently being discussed", then an anthology of recent orclassic readings is another way to go. Again, for a list, see the webpage cited above.

Iagree with Peter that the older you are, and the more you have read andstudied, the more likely it is that you will get something out of astudy of philosophy. But I think that philosophy can usefully bestudied before college (at what is called in the US the "secondary"level of education, i.e., high school) and that philosophicaldiscussions can usefully be had even earlier, at the primary, orelementary, school level. The American philosopher Gareth Matthews haswritten several wonderful books detailing his work withelementary-school kids on philosophy and has a website devoted to it: " Philosophy for Kids ". And Montclair State University has a program on both elementary and secondary education level philosophy: the Institute for the Advancement of Philosophy for Children . Inaddition, the American Philosophical Association publishes a Newsletteron Teaching Philosophy , which often treats of what is sometimes called"pre-collegephilosophy" (which term you can "google" for...