Mathematical Science Writers without PhD Is there science writers who have written on mathematics without holding a ph.d in the subject? I am aware that Robert Kanigle is one such but does there exist any other?
 A: Martin Gardner is a prototypical example, I think.
http://en.wikipedia.org/wiki/Martin_Gardner
A: William Poundstone has written some excellent books addressing mathematical topics.  One is called "Gaming the Vote," which addresses Arrow's Theorem and its implications for voting.  (Ken Arrow won the 1972 Nobel in Economics for his theorem and his work in social choice.)  Another is "Prisoner's Dilemma" which addresses Game Theory.
John Derbyshire has written a book about the Riemann Hypothesis called "Prime Obsession," which is a heroic attempt to explain the topic to amateurs.  He has also written "Unknown Quantity," about the history of algebra.
A: Nate Silver who wrote "The Signal and the Noise" holds a BA in Economics,

The book describes methods of mathematical model-building using
  probability and statistics. Silver takes a big-picture approach to
  using statistical tools, combining sources of unique data (e.g.,
  timing a minor league ball player's fastball using a radar gun), with
  historical data and principles of sound statistical analysis;
  https://en.wikipedia.org/wiki/Nate_Silver

Peter L. Bernestein who wrote "Against The Gods: The Remarkable Story of Risk" also graduated in Economics,

In 1998, it was awarded the Clarence Arthur Kulp/Elizur Wright
  Memorial Book Award from The American Risk and Insurance Association
  (ARIA) as an outstanding original contribution to the literature of
  risk and insurance.
  https://en.wikipedia.org/wiki/Peter_L._Bernstein

