coming a bit late, but one book i would really recommend as modern and easy-to-read introductory theory is the divide by jason hickel. really good analysis of modern western neo-imperialism and unequal exchange and imf/world bank shenanigans (and coups etc) that keeps the west profiting off the underdevelopment of the global south (with a brief detour into historical unsubtle imperialism). also some direct responses to why stephen pinker and bill gates etc (he fucking hates both of them) going on about the benevolence of the west making the world a better place are so full of shit

caveat that it doesnt address the important role of institutional racism in maintaining the edifice of modern imperialist exploitation, and he libs out pretty hard at the end in his proposed solutions, but an excellent and very digestible look at probably the most important issue for the left

hes also on a couple of excellent episodes of citations needed