In government, unicameralism (Latin uni, one + camera, chamber) is the practice of having one legislative or parliamentary chamber. Thus, a unicameral parliament or unicameral legislature is a legislature which consists of one chamber or house. Some countries with unicameral legislatures are often small and homogeneous unitary states and consider an upper house or second chamber unnecessary.

Unicameral legislatures exist when there is no widely perceived need for multicameralism. Many multicameral legislatures were created to give separate voices to different sectors of society. Multiple chambers allowed for guaranteed representation of different social classes (as in the Parliament of the United Kingdom or the French States-General), ethnic or regional interests, or subunits of a federation. Where these factors are unimportant, in unitary states with weak regional identity, unicameralism often prevails. Sometimes, as in New Zealand and Denmark, this comes about through the abolition of one the two chambers, or, as in Sweden, through the merger of the two chambers into a single one, while in others a second chamber has never existed.

The 100: A Ranking of the Most Influential Persons in History is a 1978 book by Michael H. Hart, reprinted in 1992 with revisions. It is a ranking of the 100 people who, according to Hart, most influenced human history.

The first person on Hart's list is the Prophet of Islam Muhammad. Hart asserted that Muhammad was "supremely successful" in both the religious and secular realms. He also believed that Muhammad's role in the development of Islam was far more influential than Jesus' collaboration in the development of Christianity. He attributes the development of Christianity to St. Paul, who played a pivotal role in its dissemination."

The 1992 revisions included the demotion of figures associated with Communism, such as Vladimir Lenin and Mao Zedong, and the introduction of Mikhail Gorbachev. Hart took sides in the Shakespearean authorship issue and substituted Edward de Vere, 17th Earl of Oxford for William Shakespeare. Hart also substituted Niels Bohr and Henri Becquerel with Ernest Rutherford, thus correcting an error in the first edition. Henry Ford was also promoted from the "Honorary Mentions" list, replacing Pablo Picasso. Finally, some of the rankings were re-ordered, although no one listed in the top ten changed position.