Writer, academic and diplomat David Dabydeen recalls five very different stories of mass migration from around the world. They move in times of crisis, fleeing war or instability, poverty or corruption. And then they face a new challenge - how to find a way to survive and prosper in new, often unfamiliar environments. David considers to what extent were these migrants were affected by the circumstances of their departure - by the violence they may have witnessed or the economic and political stresses they endured - and who bore the responsibility for their integration. Many different approaches have been tried, from large-scale mobilisation of official institutions to an almost total disengagement by the state. And the results are equally variable, suggesting that there are no easy solutions to this increasingly important dilemma. What does emerge clearly is that race, education and language all play a vital role. In this first programme, we hear the story of the Ethiopian Jews. Persecuted in the 1980s, tens of thousands have been airlifted to Israel under that country's Law of Return. Housing, healthcare and education were all provided under a meticulous assimilation plan. Yet Ethiopian Jews remain the most disadvantaged group within the Jewish population. Many have been victims of racism and tensions have boiled over, resulting in clashes in with the police. Why has the homecoming to Israel been so troubled for the first generations of Ethiopians? And are there signs that younger members of the community are determined to improve their circumstances? Producer: Hugh Costello A Whistledown production for BBC Radio 4.