?ayyim Selig ben Ya'akov Slonimski (Hebrew: ???????? ??????? ???? ???????? ??????????) (March 31, 1810 – May 15, 1904), also known by his acronym ?aZaS (????), was a Hebrew publisher, mathematician, astronomer, inventor, science writer, and rabbi.
He was among the first to write books on science for a broad Jewish audience, and was the founder of Ha-Tsfira, the first Hebrew-language newspaper with an emphasis on the sciences.