Afghanistan has been a theatre of civil and international conflict for much of the twentieth century - stability is essential if there is to be peace in the Greater Middle East. Yet policy-makers in the West often seem to forget the lessons learned from previous administrations, whose interventions have contributed to the instability in the region. Here, Sharifullah Dorani focuses on the process of decision-making, looking at which factors influenced American policy-makers in the build-up to its longest war, the Afghanistan War, and how reactions on the ground in Afghanistan have influenced events since then. America in Afghanistan is a new, full history of US foreign policy toward Afghanistan from Bush's 'War on Terror', to Obama's war of 'Countering Violent Extremism' to Trump's war against 'Radical Islamic Terrorism'. Dorani is fluent in Pashto and Dari and uses unique and unseen Afghan source-work, published here for the first time, to understand the people in Afghanistan itself, and to answer their unanswered questions about 'real' US Afghan goals, the reasons for US failures in Afghanistan, especially its inability to improve governance and stop Pakistan, Iran and Russia from supporting the insurgency in Afghanistan, and the reasons for the bewildering changes in US Afghan policy over the course of 16 and a half years. To that end the author also assesses Presidents Karzai and Ghani's responses to Bush, Obama and Trump's policies in Afghanistan and the region. In addition, the book covers the role Afghanistan's neighbours - Russia, Iran, India, and especially Pakistan - played in America's Afghanistan War. This will be an essential book for those interested in the future of the region, and those who seek to understand its recent past.