2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/20116We present a microscopic theory of superfluid $^4$He, formulated using the overall experimental observations as input information. With the theory of a consistent basis, we answer all of the essential questions regarding He II.42 pages, 10 figures; contact email (JXZJ): jxzj@mailaps.org; related paper of the authors: 1) (superfluidity mechanism): cond-mat/0206339; 2) J. de Physique IV, vol. 10, Pr7-181 (2000)Superconductivitytext