Thank you and that makes sense. I'm trying to change the code now to support redirects since it gets a different JSONObject (key is not categories for redirects) for redirects. ***one other question, for the title "Nervous system", I need to query into 3 layers. for the firs time it gives me 3 categories, 1. Nervous system 2. Neurobiology 3. Neuroscience Then I need to query each of these 3 categories to get their sub categories. but in a loop when I parse again Nervous system, it gives me the same three results but I want to get the results as I traverse in Wikipedia manually. In Wikipedia, when I search "Nervous system", it gives me these three results first and then when I click on the category Nervous system (in the initial result of categories), it gives me "Organ systems" and "Mind". How can I do this in the code with MediaWiki API? Kalpa Gunaratna ----- Original Message ----- From: Brad Jorsch <b-jorsch(a)alum.northwestern.edu> Date: Wednesday, August 3, 2011 3:28 pm Subject: Re: [Mediawiki-api] categories query does not return any results. To: MediaWiki API announcements & discussion <mediawiki-api(a)lists.wikimedia.org>