The unconditional basic income is being discussed in many places. What would we do if our existence were unconditionally secured? Would we be more diligent or lazier? Experiments are now attempting to provide answers to this question, and arguments for or against basic income are receiving wide attention. But how has this idea developed? Who has advanced it with what arguments? This volume comprehensively documents the tumultuous history of an idea that will continue to engage us in the future, using key texts from various thinkers of the unconditional basic income, including Thomas More, Charles Fourier, Bertrand Russell, John Maynard Keynes, and Philippe Van Parijs.