This Introduction provides the tools necessary for understanding the Sorites Paradox as well as a first orientation concerning its solutions and influence. After presenting the aims and the structure of the book and characterising the notion of vagueness, the Introduction presents the Sorites Paradox in its two main versions: the lack-of-boundaries version and the tolerance version. The Introduction proceeds with an overview of the solutions to the Sorites Paradox that will be developed in the volume: the ones that preserve classical logic (epistemicism, supervaluationism, contextualism, incoherentism) and the ones that do not (intuitionism, rejection of excluded middle, dialetheism, Degree theory and non-transitivism). Finally, after presenting and briefly discussing the Forced-March Paradox, the Introduction ends with a survey of the main areas in which the influence of the Sorites Paradox has been important, which are discussed in the second part of the volume.