Volume IV treats the entire Superfamily of Leguminosae, subdivided in the families Caesalpinioideae, Papilionoideae (or Fabaceae) and Mimosoideae. Each family is headed by a short family description based mainly on the more practicable field characters of leaves, inflorescences, flowers, and fruits. The section Notes includes remarks on habit, secretory systems, and seed dispersal - only when one may generalize on genus and/or family level. Following a family description, each genus within the family is numbered and mentioned together with the author's name. A genus description is given when more than one species within the genus are described. Each genus is followed by the species in alphabetical order and sub-numbered. This facilitates a quick determination of both the number of genera treated within a certain family and the number of species treated within a certain genus. The species name is followed by the author's name according to up-to-date taxonomic literature. When known to the author, vernacular names used by the most prominent sections of the population, such as Aruak-Amerindian (A), Caraib-Amerindian (C), Surinamese Dutch (SD), Spanish (Sp.), English (E), Brazilian Portuguese (B), Sranan-tongo or Surinamese (S), and Bushland-Creole, Quilombola or Paramaccan (P), have been included. When a fruit species is depicted in Volume I, plate and figure numbers are given. Plates are numbered 1-208; figures are numbered within each plate. If available, digital color photos of fruits taken in the wild are inserted below the species description. As presented in Volumes II to VI species descriptions usually include four sections, the first word of each section being printed in italics. The first section gives simple leaf characters as far as they are practicable in the field. The second section describes main characters of inflorescence, infructescence, (fruiting) calyx, and/or pedicel. The third section describes external and internal characters of fruit and seed(s). The fourth section, "Notes", gives various remarks that may be useful in the field, such as plant habit, presence of secretory systems, bark features, seed dispersal strategy, phenology, occurrence, habitat and soil type, and geographical distribution within the Guianas and the larger lowland Amazonian region. In Vol. I, I tried to include drawings of as many fruits as possible. In case of great interspecific resemblance, only one of the fruits has been depicted. Depending on the available material, fruits and seeds are drawn from different angles, cross and/or longitudinal sections, showing the morphological properties that are most important for visual identification. This Amazonian fruit catalogue includes too many species to make a usable key down to genus or species level. However, in Volumes I and IV, I have included a synoptical key to the one-hundred or so plant families treated.