Contemporary processes of urbanisation present major challenges for urban research and theory as urban areas expand and interweave. In this process, urban forms are constantly changing and new urban configurations are frequently evolving. An adequate understanding of urbanisation must derive its empirical and theoretical inspirations from the multitude of urban experiences across the various divides that shape the contemporary world. New concepts and terms are urgently required that would help, both analytically and cartographically, to decipher the differentiated and rapidly mutating landscapes of urbanisation that are being produced today. One of the key procedures to address these challenges is the application of comparative strategies. Based on postcolonial critiques of urban theory and on the epistemologies of planetary urbanisation, this paper introduces and discusses the theoretical and methodological framework of a collaborative comparative study of urbanisation processes in eight large metropolitan territories across the world: Tokyo, Hong Kong/Shenzhen/Dongguan, Kolkata, Istanbul, Lagos, Paris, Mexico City and Los Angeles. In order to approach these large territories, a specific methodological design is applied mainly based on qualitative methods and a newly developed method of mapping. After the presentation of the main lines of our theoretical and methodological approach we discuss some of the new comparative concepts that we developed through this process: popular urbanisation, plotting urbanism, multilayered patchwork urbanisation and the incorporation of urban differences.