What is the African Union?
The African Union, a successor to the decades old Organisation of African Unity (OAU), was set up in 2002 to provide a forum through which African countries might agree and adopt co-ordinated positions on international matters and defend continental interests.
The vision of the African Union is: "An integrated, prosperous and peaceful Africa, driven by its own citizens and representing a dynamic force in global arena."
There are 54 member states, the most recent member being South Sudan. The only African country never to have joined the AU is Morroco. The memberships of Mauritius, Mali and Guinea-Bissau have been suspended.
The organisation has an estimated budget of $274-million for the year 2012, about half of which is operational. With some member states failing to pay subscriptions, much of the running cost is carried by development partners, which has led to questions about who actually drives the AU agenda.
The position of AU chairperson is awarded annually, and rotates among the five regions of the AU. The post is non-renewable, and is currently held by Benin president Yayi Boni.
The AU's key decision-making body is the Assembly of Heads of State and Government, which meets once a year at the AU Summit. Its legislative body, the Pan-African Parliament, was set up in 2004 with headquarters in Midrand, Johannesburg.
The AU has a number of development programmes in progress, the most high profile of which is the New Economic Partnership for Development, or Nepad, which seeks to facilitate sustainable growth and development on the continent.
What is the AU Commission?
The AU Commission is the secretariat, or administrative body, of the AU. Its $200-million headquarters in Addis Ababa, Ethiopia, was financed by China, a generous move that raised concerns China was buying support on the continent.
This weekend, after months of intense lobbying, commission chair Jean Ping was ousted by South Africa's Nkosazana-Dlamini Zuma. Dlamini-Zuma will shortly become the first female chair of the AU.
What are its greatest successes and failures?
There has been much scepticism about the AU's effectiveness. Its origins are rooted in the OAU, which was known as a "dictators' club", and its member states differ drastically in terms of political stability and economic power.
It has had forces stationed in a number of conflict-ridden countries, including Somalia, Burundi, the DRC and Côte d'Ivoire, and in 2008 even invaded the Comores island of Anjouan to topple a renegade leader. But its track record in mediating political standoffs has been generally poor. It has been criticised for failing to defuse conflict in Darfur and Somalia, a task made more difficult by its lack of funds and political will.
What are its immediate challenges?
The AU has denied that its authority has been affected by the protracted leadership struggle between Ping and Dlamini-Zuma, which began early this year and ended just this weekend. But this year has already seen military coups in both Mali and Guinea-Bissau, and increased violence from extremist groups in Nigeria and the Sahel.
Tension has also been brewing between Sudan and South Sudan, the newest member of the organisation. Dlamini-Zuma's immediate challenges will be to address these conflicts and, in particular, to gain UN backing for a military intervention in northern Mali.
She will also need to mend fences following the heated leadership battle, which has alienated many Francophone countries that supported Ping for a second term as chair, and to convince the continent's smaller countries that South Africa will not seek to dominate the organisation.