Henry Laurence Gantt (1861-1919) was a mechanical engineer, management consultant and industry advisor. He developed Gantt charts in the second decade of the 20th century as a visual tool to show scheduled and actual progress of projects. Accepted as a common-place project management tool today, it was quite a radical concept and an innovation of world-wide importance in the 1920s.  Gantt charts were first used on large construction projects like the Hoover Dam, started in 1931 and the interstate highway network which started in 1956.  Download Organizing for Work, a book by Henry Gantt.