NOVELTY - The method involves using distillation column system containing two distillation columns.    USE - Used in to separate multi-component mixtures containing three or more components into product streams each enriched in one of the components.    ADVANTAGE - Provides more efficient separation by reducing the heat requirement of the distillation columns within the distillation scheme.    DETAILED DESCRIPTION - The process of separating a feed stream into respective product steams that are enriched in one of the major constituent components comprises using at least two distillation columns in the distillation, and involves:    (a) feeding the feed stream containing three or more major constituent components to a column of the distillation column system;    (b) producing a vapor steam enriched in the most volatile major constituent component at the top of one of the distillation columns (First distillation column) in the distillation column system and providing reflux to the first distillation column by feeding to the top a liquid steam enriched in the most volatile major constituent component;    (c) producing a liquid steam enriched in the least volatile major constituent component at the bottom of a distillation column (second distillation column) that is different from the first distillation column and providing vapor boilup to the second distillation column by feeding to the bottom a vapor stream enriched in the least volatile major constituent component;    (d) operating the second distillation column such that the operating pressure at the location where a vapor state is removed to be fed to another distillation column of the distillation column system is greater than the operating pressure at the location of another distillation column where the vapor steam is fed;    (e) feeding a first vapor steam removed from a first location of the second distillation column to another distillation column of the distillation system; and    (f) feeding a second vapor steam removed from a second intermediate location of the second distillation column to another distillation system; and feeding a vapor stream removed from another distillation column of the distillation column system to the first distillation column.    Preferred Features: A portion of the most volatile major constituent component enriched vapor produced from the top of the first distillation column is at least partially condensed and at least a portion of the condensed stream is fed as the liquid stream reflux to the first distillation column.    An INDEPENDENT CLAIM includes an apparatus for the separation by the above mentioned process.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic view of the process.