Freemasonry is generally accepted as having begun with the traditions of the stonemason's guilds in England and Europe in the Middle Ages. In 1717, a "union" of four "guilds" (or Lodges) took place in London, which formed the start of modern day Freemasonry.
As time went on, Freemasonry spread over the face of the earth - in early American history, some noted Freemasons were George Washington, Benjamin Franklin, Joseph Warren, Paul Revere, Lafayette, John Paul Jones, John Hancock, and others.
Masons have been leaders in public education, being amongst the first supporters of a public school system in America as well as in Europe, and Masonic support of education continues today. As a fraternity, Freemasonry emphasizes self-improvement, personal study and the betterment of society through both self-enrichment and philanthropy. Freemasons today contribute about two million dollars per day (yes, per DAY!) to charitable causes ranging from funding medical research to operating children's hospitals.
Freemasonry is not a religion, nor a substitute for a religion - yet it requires that its members affirm a belief in a Supreme Being. Freemasonry forbids sectarian discussion in its Lodge rooms, yet it has an open "Volume of the Sacred Law" on its altar - to provide a "rule and guide for life". Freemasons take a vow of obligation - to follow the principles of the organization, and to protect and keep secret its methods of recognition. Freemasonry encourages each member to practice his own faith and to observe his duty to his own Supreme Being in his own ways. The moral teachings of Freemasonry are acceptable to all faiths.
Freemasonry is not a "Secret Society", but a "Society with Secrets" - in that our buildings are publicly recognizable, our members display emblems of membership, our Lodges are listed in the public telephone directories, our meetings are publicized . . . it is only our "methods of recognition" and the content of our meetings that are not public. We are no more of a "Secret Society" than someone who will not publicly post the contents of their check register is a "Secret Society". In terms of what it does, what it teaches, who belongs, or where it meets, there are NO secrets in Freemasonry. Freemasonry is a private, fraternal organization of men who contribute much toward the public good, while enjoying the benefits of the brotherhood found in a fraternal organization.
(Some of the above content was derived from a series of papers on Freemasonry, published by the Masonic Services Association of North America, available at http://www.msana.com.)