Letteris was a member of a family of printers that originally came from Amsterdam. At the age of twelve he sent a Hebrew poem to Nachman Krochmal, who was then living at Zolkiev. Subsequently he made the acquaintance of Krochmal, who encouraged him in his study of German, French, and Latin literature. In 1826, he entered the University of Lemberg, where for four years he studied philosophy and Oriental languages. In 1831, he went to Berlin as Hebrew corrector in a printing establishment, and later in a similar capacity to Presburg, where he edited a large number of valuable manuscripts, and to Prague, where he received the degree of Ph. D.. In 1848 he settled finally in Vienna. Letteris' chief poetical work in German, Sagen aus dem Orient, consisting of poetic renderings of Talmudic and other legends, secured for him, though for a short time, the post of librarian in the Oriental department of the Vienna Imperial Library. His reputation as the foremost poet of the Galician school is based on his volume of poems Tofes Kinnor we-'Ugab, and especially on his Hebrew version of "Faust," entitled "Ben Abuya". He exerted a considerable influence on Hebrew poetry. One of his best poems is his Zionistic song Yonah Ḥomiyyah, became very popular. His numerous translations are of value, but his original poems are as a rule prolix. His Hebrew prose is correct, though heavy. In his Hebrew version of Faust, Faust is replaced by the Jewish heretic Elisha ben Abuyah. For the infidelity of his "translation" to Goethe's original, Letteris was the object of a blistering attack by the young Peretz Smolenskin.
The Letteris Bible
In 1852, during a period in which he faced financial difficulties, he agreed to edit an edition of the masoretic text of the Hebrew Bible. In 1866 he produced a revised edition for a Christian missionary organization, the British and Foreign Bible Society. This revision was checked against old manuscripts and early printed editions. Its typeface is highly legible and it is printed in a clear single-column format per page. It is probably the most widely reproduced text of the Hebrew Bible in history, with many dozens of authorised reprints and many more pirated and unacknowledged ones. This revised edition became very popular, and was widely reprinted in both Jewish circles and in Christian circles.
Other works
Besides the works already mentioned the following deserve special notice:
Dibre Shir and "Ayyelet ha-Shachar", including translations from Schiller and Homer, and poems by Letteris' father
Ha-efirah, a selection of poems and essays
Palge Mayim, poems
Gedichte, German translations from the Hebrew
Geza' Yishai, Hebrew translation of Racine's "Athalie"
Shelom Ester, Hebrew translation of Racine's "Esther"
Spinoza's Lehre und Leben
Neginot Yisrael, Hebrew rendering of Frankel's "Nach der Zerstreuung"
Bilder aus dem Biblischen Morgenlande.
He was the editor of Wiener Vierteljahrsschrift, with a Hebrew supplement, Abne Nezer, and of Wiener Monatsblätter für Kunst und Litteratur.