Tehillat Hashem (תְּהִלַּת ה', "praise of God" in Hebrew) is the name of a prayer-book (known as a siddur in Hebrew) used for Jewish services in synagogues and privately by Hasidic Jews, specifically in the Chabad-Lubavitch community.
Tehillat Hashem Siddur is an edition of the Siddur Harav or Siddur Admur Hazaken, edited and published by Rabbi Shneur Zalman of Liadi (1745-1812) the founder of the Chabad-Lubavitch movement, and follows the teachings of Rabbi Isaac Luria. First published in Rostov, Russia in 1918-1920, and later in 1945 an enlarged, completed edition of this Siddur was published by the Merkos L'Inionei Chinuch in Brooklyn, New York. It is the most popular Siddur in the world (as it is used by the 300,000 Chabad families worldwide).
Another Edition of Siddur Admur Hazaken is called Siddur Torah Ohr
English Translations
Tehillat Hashem Siddur was first translated to English by Rabbi Nissen Mangel and published in 1978, Later another translation was made by Rabbi Eliyahu Touger, and a Youth Translation was made by an editorial team and published in 2012-2014.