Landau was a recognized authority in rabbinical matters, and many authors solicited his approbation of their works. He himself was a prolific writer, and was the author of the following commentaries: • ''Ma'aneh Eliyahu
(Vilna, 1840), on the Tanna debe Eliyahu, accompanied with notes on other subjects under the title Siaḥ Yiẓḥaḳ'' • A double commentary on the
Mekhilta (ib. 1844):
Berurei haMiddot, on the text, and
Mitzui haMiddot, glosses to the
Biblical and
Talmudic passages quoted in the commentary •
Patshegen (ib. 1858), on
Proverbs •
Miḳra Soferim (Suwalki, 1862), on
Masseket Soferim •
Dober Shalom (Warsaw, 1863), on the daily prayers •
Kiflayim leTushiyyah, on the twelve
Minor Prophets (only that on
Joel published, Jitomir, 1865) and on
Psalms (Warsaw, 1866) •
Patshegen haDat, on the
Five Scrolls (Vilna, 1870) and on the
Pentateuch (ib. 1872–75) •
Aḥarit leShalom (ib. 1871), on the
Pesaḥ Haggadah •
Derekh Ḥayyim (ib. 1872), on
Derek Ereẓ Zuṭa • ''Lishmoa' kaLimmudim'' (ib. 1876), on the
aggadah of the
talmudists •
Simlah Ḥadashah, on the
Maḥzor (published in the Vilna editions of the Maḥzor) Landau published also
Derushim le-Kol Ḥefẓehem (ib. 1871–77), a collection of sermons; and two of his funeral orations:
Ḳol Shaon (Vilna, 1872; also translated into the
Russian language), on the wife of
Prince Potapov; and
Ebel Kabed (Eydtkuhnen, 1873), on
Samuel Straschun. He left besides a number of works still unpublished as of 1906. ==References==