The fourth book to the left is "The Concept of Dread."
The Concept of Dread was a philosophical work by Kierkegaard.
In 2399, this was one of the books in Cristóbal Rios' library in his quarters aboard La Sirena. (PIC: "Broken Pieces")
The Concept of Dread was the title given by a translator to the work The Concept of Anxiety (Begrebet Angest), which was published in 1844.