The One Thing: The Surprisingly Simple Truth Behind Extraordinary Results is a non-fiction, self-help book written by authors and real estate entrepreneurs, Gary W. Keller and Jay Papasan. The book discusses the value of simplifying one's workload by focusing on the one most important task in any given project.
Productivity describes various measures of the efficiency of production. Often, a productivity measure is expressed as the ratio of an aggregate output to a single input or an aggregate input used in a production process, i.e. output per unit of input, typically over a specific period of time.