The Roads Must Roll - Robert A. Heinlein
What a plot it is, both literally and storywise. Heinlein explores social order, industrialization and technology of the near/far future with a flair for prose and a paced storytelling. The mechanical roads that replace the conventional highways and motor vehicles have transformed the entire face of future society. The immaculate details of its functionality makes it less science fiction and more science. Heinlein takes the reader through an visionary journey that is technical, philosophical and grittily visual.