[en] The formation and destruction of interstellar dust grains is reviewed. Difficulties are pointed out for the ''two-phase model'' of clouds and intercloud medium in complete pressure equilibrium. Central stars of very old planetary nebulae are advocated for ionizing parts of the intercloud medium. Supernova remnants are advocated for enhancing density variations and for providing bulk kinetic energy to interstellar clouds. A scaled-down version of the ''two-phase model'' is resurrected, but with a highly heterogeneous intercloud medium