Abstract
According to the liquid-liquid critical point hypothesis of water, liquid water separates into low- and high-density liquid phases at low temperature and high pressure, and these liquid phases become the known low- and high-density amorphous ices below their glass transition temperatures. An accumulation of experimental and theoretical results seems to support this hypothesis, and this hypothesis may virtually explain "the mysteries of water" including the density maximum at 277 K. Aqueous solutions and the confined water appear to be readily interpreted on the hypothesis.