Following each title is the year in which the book is most likely set. In some books, L'Amour has his protagonist explicitly give the year. In others, the year can be determined by some historical reference used by the author such as in "Chancy" when Chancy tells of meeting Wild Bill Hickock in Abilene. According to Wikipedia, historical records show that Hickock was marshal of Abilene only in the year of 1871 which makes the setting of "Chancy" to be 1871. Other books are given their place in the chronology based on references by characters or events that indicate a book's place in the chronology.