Method for selectively defiberizing and delignifying lignocellulose employing a novel alkaline pulping system. The subject pulping system includes a pulping liquor comprising water, a water-miscible organic reagent, and a sulfide or bisulfide compound selected from the group consisting of alkali metal sulfides and bisulfides, ammonium sulfide and ammonium bisulfide. Extremely high pulp yields as compared to kraft pulping are provided by employing the method and system of this invention.