You can find numerous excerpts from Ron Paul's past publications here.
When I asked Jesse Benton, Paul's campaign spokesman, about the newsletters, he said that, over the years, Paul had granted "various levels of approval" to what appeared in his publications--ranging from "no approval" to instances where he "actually wrote it himself." After I read Benton some of the more offensive passages, he said, "A lot of [the newsletters] he did not see. Most of the incendiary stuff, no." He added that he was surprised to hear about the insults hurled at Martin Luther King, because "Ron thinks Martin Luther King is a hero."
In other words, Paul's campaign wants to depict its candidate as a naïve, absentee overseer, with minimal knowledge of what his underlings were doing on his behalf. This portrayal might be more believable if extremist views had cropped up in the newsletters only sporadically--or if the newsletters had just been published for a short time. But it is difficult to imagine how Paul could allow material consistently saturated in racism, homophobia, anti-Semitism, and conspiracy-mongering to be printed under his name for so long if he did not share these views. In that respect, whether or not Paul personally wrote the most offensive passages is almost beside the point. If he disagreed with what was being written under his name, you would think that at some point--over the course of decades--he would have done something about it.