Hi,
Before we get started, I think that your question is about identifying the Library of Congress subject headings that would be used in the library catalog to classify materials about reading. If your question is actually about something else, please write back and clarify what you really meant!
To find subject headings, start by going to the Bailey Library catalog. In the "Search By" menu, choose "subject keyword." This option will show you all of the subject headings that contain the word you enter, anywhere in the heading. If you type in "reading," you'll see a list of several hundred subject headings and subheadings which include the word "reading."
Another way to search is to choose "Subject Heading Search" from the catalog menu. This option searches for headings that start with the word you enter. When you type in "reading," you'll see that the main heading "Reading" has a little oval next to it that says "Note/Ref." (Other headings may have an oval that says "info.") By clicking on the oval, you can read a note from a cataloger that explains what the subject heading means and suggests some others you might want to try.
To find headings for "reading," I think these two techniques will work. However, for some topics, the subject headings are hard to guess. A "back way" to find the right headings is to look up the title or author of a book already you know deals with the subject you want. The full record (accessible by clicking the title in our catalog) will contain the subject headings for that book. These are clickable links that take you to see the list of headings beginning with that entry.
I hope this helps! If this wasn't quite what you wanted to know, or if you still have questions, feel free to write back, or stop by or call.
Best,
Alex Boyd