Often, an academic writer is trying to fill a niche. Now, the niches are getting smaller. Academics may write for large audiences on their blogs or as journalists. But when it comes to their academic writing, and to the research that underpins it—to the main activities, in other words, of academic life—they have no choice but to aim for very small targets. Writing a first book, you may have in mind particular professors on a tenure committee; miss that mark and you may not have a job.