He argues that British Imperialism was unique (one of our contentious themes),  "genuinely different from other brands" (p. 7). What was different?

       By p.11 he claims the reader is, and should be, more confused than ever about British Imperialism!

      On p.14 (second ¶) he slips a definition in almost covertly, then backs off it on the next page with his "informal empire" vague-arity. Then he hides in details in the next pages, and in the debate of the Victorian "constant dilemma" (p.23) and in the definitional dodge of "cultural imperialism" after that (pp.36ff).

      Can we make sense of Porter's groping for understanding out of the detail? Out of the groping? Out of the debates and dodges? What is going on?

       We need to make sense of this if we are ever to understand the Indian Revolt or the rest.... Guns/ships-ability, banks, markets, religion, culture, power, security, humanitarian Omelettes, raw materials, personal adventure, wealth, social Darwinism, Gunga-Din-Globalism--

        And if we are to understand the significance of English Imperialism for the United States (our theme of the U.S. as 'heir' to Britain), then we need to get the complex issues surrounding imperialism under control: one way is to peek ahead.
        Porter's conclusion swirls around many of these issues (pp. 351-370). What are Porter's conclusions? Give these 19 pages a 'close read' and note as many issues, observations, suggestions, implications etc that you see.

The Victorian Web has a short summary/explanation of British Imperialism

The British Empire was large & diverse, and so it this website.