Destiny's Road
The book follows the life of Jemmy Bloocher, (who changes his name several times) as he travels the planet called Destiny, a colony founded over 200 years earlier.  The "Road" is a long trail laid down by the founders.  Only the Caravans travel the full length of the road as they bring (or sell) "speckles" to settlers who, without them, would suffer severe potassium deficiency leading to brain damage.  The Caravans control who gets speckles and therefore effectively control the whole world.  Jemmy sets off to find answers to questions the Caravan Merchants won't give him.  In the process, we get a good look at the world and also at it's economy.  Larry Niven's world-building skills are phenomenal, and this book is a good example of just that.  There is room to develop the native alien sapients ("Otterfolk") further, perhaps in a sequel.  

This is "hard" science fiction in that the medical (potassium) and economic (hydraulic empire, resource domination) foundations of the book are soundly researched. But it is relatively "soft" for "hard" fiction, as there is very little exposition or explanation of the science involved.
Hydraulic Empire, Science Fiction, American Science fiction, Fiction, science fiction, general
Larry Niven
Laurence van Cott Niven — known as Larry Niven — is an American science fiction writer. His best-known work is Ringworld (1970), which received Hugo, Locus, Ditmar, and Nebula awards. The Science Fiction Writers of America named him the 2015 recipient of the Damon Knight Memorial Grand Master Award. His work is primarily hard science fiction, using big science concepts and theoretical physics. It also often includes elements of detective fiction and adventure stories. His fantasy includes the series The Magic Goes Away, rational fantasy dealing with magic as a non-renewable resource.

Niven was born in Los Angeles. He briefly attended the California Institute of Technology and graduated with a Bachelor of Arts in mathematics (with a minor in psychology) from Washburn University, Topeka, Kansas, in 1962. He did a year of graduate work in mathematics at the University of California at Los Angeles. On September 6, 1969, he married Marilyn Joyce "Fuzzy Pink" Wisowaty, a science fiction and Regency literature fan. He is an agnostic.

Source: Wikipedia