I only know one, so this must be it. When I still lived in Rochester, NY, Henlein came to speak, and the event was written up in the local paper. Apparently the audience was filled with unwashed types who wanted to hear about grokking. But Heinlein showed up in a dinner jacket and gave a nuts and bolts talk about how to write, and how to get published. The two cultures indeed.

When Heinlein died, Mark Cunningham wrote our obit, and a very good job he did too. But I remember that he quoted some blistering denunciation by the deceased of Samuel Johnson (for saying that patriotism is the last refuge of a scoundrel). I took it out (I was Managing Editor then) on the grounds that NR would not attack Samuel Johnson.