Neutral (grounded conductor) for bathroom switch (NEC 404.2(C))?
Your book is faulty -- 404.2(C) may not have required neutrals at bathroom light switches at one point in time, but it certainly does in the current (2014) NEC!


  C) Switches Controlling Lighting Loads. The grounded circuit conductor for 
  the controlled lighting circuit shall be provided at the location where switches 
  control lighting loads that are supplied by a grounded general-purpose branch 
  circuit for other than the following:
  
  (4) Where a switch does not serve a habitable room or bathroom