The Commonwealth is a voluntary organization of sovereign states consulting and cooperating in the common interest of their peoples and in the promotion of international understanding and world peace. (Preamble to the Declaration of Commowealth Principles). In 1997 the commonwealth consisted of 54 member countries with a shared committment to certain fundamental principles as set out in the Declaration of Commonwealth Principles and the Harare Commonwealth Declaration, the Commonwealth's second general statement of beliefs.
According to the Commonwealth Yearbook 1998, the Commonwealth member states numbered 54. Commonwealth member countries are culturally, politically and economically diverse. In addition, member countries are located in almost every continent. Amonst the most industrialized members are Britain, canada, Australia. On the other hand, some of the poorest countries in terms of per capita GNP are Tanzania, Bangladesh. Commonwealth members are also politically diverse:
| Parliamentary Monarchies | Republics | National Monarchies |
| Antigua, Australia, The Bahamas, Belize, Dominica, Grenada, Jamaica, New Zealand, St. Kitts & Nevis, St. Lucia, St. Vincent and Grenadines, Papua New Guinea, Samoa, Sierra Leone, Salomon Is., Tuvalu | Bangladesh, Botswana, Cameroon, Cyprus, Mauritius, The Gambia, Ghana, Guyana, India, Kenya, Kiribati, Malawi, Maldives, Malta, Mozambique, Namibia, Nauru, Nigeria, Pakistan, Seychelles, Singapore, South Africa, Sri Lanka, Tanzania, Trinidad & Tobago, Uganda, Vanuatu, Zambia, Zimbabwe | Brunei Darussalam, Lesotho, Malaysia, Swaziland, Tonga |
Three countries rejoined the Commonwealth. South Africa withdrew in 1961 and was readmitted in 1994 after a democratic election. Pakistan left in 1972, and returned after the democratic elections in 1989. Fiji's membership lapsed in 1987 and was welcomed back in 1997 after embarking a constitutional reform from a military coup, which was contrary to Commonwealth principles.
Nigeria was suspended in November 1995.
Membership is not restricted to former British colonies as witnessed by the admittance of Cameroon and Mozambique. However, only independent states can become member.
The Queen is Head of State in 17 fully independent Commonwealth countries. This role carries no formal function but is symbolic.
Commonwealth countries are increasingly developing their own model of Company Law tailored to local circumstances. Generally, most Commonwealth countries have a legal system based on English Common Law, however countries like Canada, Cameroon, Mauritius, Malta and Seychelles derived their legal system from the Code Napoleon with some mixtures of both systems. While other countries, such as South Africa, Botswana, Guyana, Lesotho, Mozambique, Sri Lanka, Swaziland, Zimbabwe practice a mixture of law based on Roman Dutch Law and British Common Law. In addition, there are some exceptional cases: some members practice Islamic Law (Brunei Darussalam, Maldives and Pakistan). Commercial Law British law is frequently selected by most member states to govern relationships of foreign contracting parties principally because of historical links where countries like The Bahamas and Barbados recognize the Privy Council as final court of appeal.