It would really help if you could learn the correct terminology (using the wrong terminology suggests that you haven't grasped the basic concepts). When you talk about "omitting the run tag", I strongly suspect that you mean "omitting the run element". Remember that an element has two tags, a start tag and an end tag. I suspect you want to omit the content between the tags (that is, the children of the element node) as well as the tags themselves.
will output the string value of the element - that is, its contained text - without any tags. That's what you asked for, but I suspect it's not what you want.
I'm not really sure what you do want, but if you only want the content of title elements that do not have a run child element, it would be
Author, XSLT 2.0 and XPath 2.0 Programmer's Reference