This thesis explores how the world's poor have been faring since the 19th Century. Chapter 1 analyses how the distribution of income among the world's countries has progressed since 1870, showing that there has been a divergence in incomes among the rich and poor countries over the period. Chapters 2 and 3 then look at the trends in poverty since 1820, at the overall world level, and then in six of the world's regions. We see that once the analysis is taken to the individual level, the data show that the welfare of the poor has improved significantly over time : there has been an enormous reduction in poverty rates over the period. And while the beginning of the period saw an increase in the number of people living below the poverty lines, since the middle of the 20th Century poverty headcounts have also been falling