One such song with a mysterious origin story is “You Are My Sunshine,” a classic, bright folk tune born of love and brightness that has subsided through the years.

The official state song is “ Give Me Louisiana,” written in 1970 by Doralice Fontane, and not only former Gov. Jimmie Davis’ version of “ You Are My Sunshine, ” as many thought.

Robert Mann’s 10th book, “You Are My Sunshine: Jimmie Davis & the Biography of a Song,” wraps musicology and social and political history into 161 concise pages.

Watch Chris and Morgane Stapleton perform a slow, swampy "You Are My Sunshine" in 2013.

A Georgia songwriter wrote "You Are My Sunshine", but he didn't try to copyright quickly enough and someone else beat him to the punch.

Robert Mann's new book "You Are My Sunshine” explores the iconic song and its place in the culture and history of Louisiana and America.