Semiotics is the discipline studying the meanings, uses, and functions of signs and sign systems—a “sign” being defined as anything (a word, gesture, facial expression, and so on) that stands for something other than itself, to someone, in some capacity. Some designate this discipline as a science, others as an analytical tool or a critical method. One of its modern-day founders, the American philosopher Charles Sanders Peirce (b. 1839–d. 1914), called it a “doctrine,” in the sense of a set of principles. It has also been called “semiology” by Ferdinand de Saussure (b. 1857–d. 1913), another modern-day founder. The terms “significs,” coined by Victoria Lady Welby (b. 1837–d. 1912), and “sematology” are also sometimes used. The term “semiotics” was adopted by the International Association for Semiotics Studies in 1969, becoming, ever since, the main one to designate the discipline. Debate is ongoing today about whether semiotics is a science and if it should encompass the study of nonhuman as well as human sign systems. This has led to the rise to prominence of “biosemiotics,” which aims to do exactly that. Several theoretical debates have also characterized semiotics proper for more than a century. The most important one has been whether sign construction is, in its origin, an arbitrary process, producing sign forms with no sensory, experiential, or affective connection to their referents, or if it is a “motivated” process, or generating sign forms that do. This basic debate is discussed in several core texts and in many of the theoretical works listed here. In a general annotated bibliography such as this one, selections must be made, given the extensive amount of writing that has marked the field over the past century. Also, decisions have to be made to classify certain works under particular rubrics, rather than others, because of the built-in thematic overlap of a large portion of semiotic writing. So, some listings included here under one category may be found classified under some other category elsewhere. Also, only English-language works have been listed here. This in no way implies that works in other languages are less important. On the contrary, many non-English works have been critical to the establishment and development of semiotics as a discipline. They are not included here unless they have English translations.