CIECHANOW (Tsekhanov), ABRAHAM BEN RAPHAEL LANDAU OF ("Czechanower"; 1789–1875), rabbi, author, and ḥasidic ẓaddik of Poland; talmudic scholar and ascetic. His family name was originally Dobrzinsky but when he married the daughter of Dan Landau, the parnas of Polock (Polotsk), who supported him for many years, he changed it to Landau. Abraham's mentor in *Ḥasidism was R. Fishel of Strykow. He was an admirer of *Simḥah Bunim of Przysucha whom he twice visited. In 1819 Abraham was appointed rabbi of Ciechanow, where he officiated until his death. Although invited to serve as rabbi in Lodz, Lublin, and Polock he refused to leave the smaller community. From 1866 he was acknowledged as a ẓaddik by the Ḥasidim in Ciechanow, but continued to follow the Ashkenazi rite contrary to usual ḥasidic practice. He never followed the custom of receiving "petitions" or money from his followers. Abraham frequently took part in consultations over public matters of Jewish interest. In general adopting a stand of extreme conservatism, he strongly opposed the order of the Russian authorities that Jews should modify their dress. His published works include Ahavat Ḥesed (1897) on the orders Nashim and Tohorot; Zekhuta de-Avraham (1865), sermons; and Beit Avraham (1899) on halakhic questions. Almost all his sons were ẓaddikim. The eldest and most prominent was ZE'EV WOLF OF STRYKOW (1807–1891), regarded as the "wisest" of the pupils of Menahem Mendel of *Kotsk (Kock), author of Zer Zahav (1900), on the Torah. He wrote poetry and had an elegant Hebrew style. Other sons of Abraham were JACOB OF JASOW (1834–1894); and DOV BERISH OF BIALA (1820–1876). Abraham's grandsons were also ẓaddikim.