New tools are introduced for the study of homogeneous continua. The subcontinua of a given continuum are classified into three types: filament, non-filament, and ample, with ample being a subcategory of non-filament. The richness of the collection of ample subcontinua of a homogeneous continuum reflects where the space lies in the gradation from being locally connected at one extreme to indecomposable at another. Applications are given to the general theory of homogeneous continua and their hyperspaces. This is the introductory paper in a series of articles [18,17,19,16] which develop and apply new tools in continuum theory based on the concepts of filament and ample subcontinua. These techniques are especially suited to studying homogeneous continua as well as a larger, well known, class of spaces, which we refer to as Kelley continua.The topic of homogeneous continua has been a classic since 1920, when Knaster and Kuratowski asked about such continua in the plane [9]. Homogeneous continua form a natural class of spaces, with remarkable examples such as the pseudo-arc, solenoids, and the Menger universal curve, to mention just a few. Interest in homogeneous continua over the decades has opened new areas of mathematical research going far beyond homogeneity. Despite the obvious attention, progress in classifying homogeneous continua could be characterized as slow with sporadic bursts of activity resulting from the introduction of new tools such as the aposyndetic decomposition theorem of Jones [7], its improvements by Rogers [20,21,23], and the Theorem of Effros [4, Theorem 2]. The present case appears to be another such event. The tools which we offer also connect with another, quite different, area of intense interest in topology: the hyperspace of subcontinua of a given continuum.In a continuum X, the subcontinua fall naturally into two mutually exclusive types which we call filament and non-filament. A subcontinuum F is filament if it has a neighborhood in which the component containing F has empty