This book brings together essays written in the course of twenty-five years of teaching, reflections, and research on Nigeria, South Africa and Africa at various academic institutions in Africa and the United States. As such, these essays reflect successive stages of my evolving thinking about Nigeria, South Africa and Africa's international relations. As the title suggests, the common thread that binds these essays together are challenges confronting Africa, opportunities for Africa, and the changes that are needed, viewed, as major issues facing Africans in the twenty-first century. In other words, the theme of the essential political, economic and cultural unity of Africa, as eloquently advocated by Kwame Nkrumah under-girds these essays. The essays in this book show that six centuries of unequal and asymmetrical relations between Africa and Europe characterised by domination and exploitation through the successive historical processes of slavery, commercialism, imperialism, colonialism, neo-colonialism and globalisation have left Africa undeveloped, marginalised, and still politically, economically and culturally dependent on the Western powers as never seen before in our historical relations with the West.