What Is the Best Way to Write for a Wide Audience?

After freconomics came out and we had some success in terms of publishing, a historian that i knew grumbled that he would never want a wide audience to read his scholarship. It's an interesting and it's a sad question, because understanding of science is essential for the broad public. So it's ironic that academics should make it difficult for those who want to explain the excitement they work to thebroad public.