Brainin is the author of several pamphlets, the most important of which are his sketch of Perez Smolenskin's life and works, Warsaw, 1896; and a translation of M. Lazarus' essay on Jeremiah, Warsaw, 1897. He has also written about one hundred biographical sketches of modern Jewish scholars and writers.
To "Ahiasaf" Brainin has contributed the following articles: "Ilane Srak" (Barren Trees) (i. 32); "Bar Halafta" (ii. 71); "Dappim Mekutta'im" (Loose Leaves) (v. 120). He has also contributed to the same periodical the following biographical sketches: M. Lazarus (iv. 214); M. Güdemann (iv. 219); Theodore Herzl (v. 222); Israel Zangwill (v. 233); and Max Nordau (v. 247).