This article deals with optimism from a descriptive point of view, focusing on the different views offered by four interesting essays: Optimism by Hellen Keller (1903), an autobiographical book in which the author, deaf, blind and dumb, shows her passion for life; "Candide, ou l'Optimisme" (1979) an ironic fable in which Voltaire jests at naive optimism; El optimismo inteligente (1998), an essay in which Maria Dolores Avia and Carmelo Vazquez seek to delimit the semantics of the term optimism; and Invitacion al optimismo (2004) by Miguel Angel Santos Guerra, a hopeful hymn to the power of optimism. Finally, we briefly introduce the articles in this special issue.