Wikipedia
Roadmarks is a science fantasy novel written by Roger Zelazny during the late 1970s and published in 1979.
The novel postulates a road that travels through time, with a nexus placed every few years where a handful of specially gifted people are able to get on and off. While there is a plot involving a series of assassination attempts on the protagonist, the novel's main strengths lie in the unique nature of the setting, character development, structure and the short vignettes on each of the would-be assassins.
The book is also notable for having two famous poetry collections as characters. " Les Fleurs du Mal" by Charles Baudelaire and " Leaves of Grass" by Walt Whitman appear as cybernetic extensions of themselves. They are companions of the protagonist and his son Randy, and are referred to as "Flowers" and "Leaves" respectively. Both talk, argue and quote their own content frequently, exhibiting human-like intelligence to such degree that it seems certain they could easily pass the Turing test.
The novel alternates between non-linear "Two" and linear "One" chapters. Zelazny explained, "I did not decide until I was well into the book that since there was really two time-situations being dealt with (on-Road and off-Road—with off-Road being anywhen in history), I needed only two chapter headings, One and Two, to let the reader know where we are. And since the Twos were non-linear, anyway, I clipped each Two chapter into a discrete packet, stacked them and then shuffled them before reinserting them between the Ones. It shouldn't have made any difference, though I wouldn’t have had the guts to try doing that without my experience with my other experimental books and the faith it had given me in the feelings I’d developed toward narrative." The book's editor was confused by the "Two" chapters and required Zelazny to rearrange the order of a few of them before publication.