We are reprinting this article by Jack Treynor, which first appeared in the May/June 1976 issue, as a companion to Stephen J. Brown’s Editor’s Corner about Treynor’s legacy. Treynor distinguishes between ideas whose implications are obvious and consequently travel quickly and ideas that require reflection, judgment, and special expertise for their evaluation and consequently travel slowly. According to Treynor, the second kind of idea is the only meaningful basis for “long-term investing.”