The author looks at the interplay of forces at work when the union of Tanganyika and the island nation of Zanzibar was formed in April 1964: Cold War intrigues and rivalries; Pan-African solidarity and commitment to regional and continental unity among other factors. What role, if any, did the Cold War play in facilitating the merger of the two East African countries? Was it an African initiative by the nationalist leaders of Tanganyika and Zanzibar to unite the two countries? Did Pan-Africanism and pan-African solidarity play a primary or a minor role? Or was it the prime determinant? Other factors include fear of a communist regime which could have been established in Zanzibar after the revolution, turning the island nation into what the United States and other Western powers feared would be “the Cuba of Africa”; security concerns by Tanganyika if Zanzibar, so close to the mainland, were to have a hostile regime or became unstable, thus posing a threat to the mainland; fear by Zanzibari leaders especially President Abeid Karume who was worried that his political enemies, especially the Marxist-Leninist Abdulrahman Mohamed Babu, could oust him from power and the only way he could be secure would be by uniting his country with Tanganyika for protection by a bigger and more powerful neighbour. What role, if any, did all those factors play in the unification of the two countries? Why did Zanzibari leaders such as Kassim Hanga and even Abdulrahman Babu, well-known Marxist-Leninists, support the union with Tanganyika, knowing full well that it would deprive them of their power base in Zanzibar and thus make them “allies” of their enemies, the United States and other Western powers who encouraged the merger of the two countries to neutralise them to prevent them from establishing a communist regime in Zanzibar that would pose a threat to Western geopolitical and strategic interests in the region and in Africa as a whole? And why do the leaders of Tanzania mainland want to maintain the union at any cost although Zanzibar is an economic burden on the mainland? The book includes some declassified material and interviews with senior American diplomats who were in Tanganyika and Zanzibar when the merger of the two countries took place.