The Tatar language alphabet has undergone many changes over the centuries. This overview is taken from Omniglot:
Tatar is a Turkic language with about 7 million speakers in Russian republic of Tatarstan, and also in Afghanistan, Azerbaijan, Belarus, China, Estonia, Finland, Georgia, Kazakhstan, Kyrgyzstan, Latvia, Lithuania, Moldova, Tajikistan, Turkey (Europe), Turkmenistan, Ukraine, USA and Uzbekistan.
Tatar has been written with a number of different alphabets: before the 9th century AD it was written with the Orkhon alphabet; then with a version of the Arabic alphabet until 1920. A modified version of the Arabic alphabet known as Yaña imlâ or new orthography was used between 1920 and 1927. Since then it has been written with the Cyrillic alphabet and a number of versions of the Latin alphabet.
Arabic alphabet for Tatar
Tatar was written using the variant of the Arabic alphabet shown below from the 9th century until 1920.
Latin alphabet for Tatar (Jaŋalif)
Between 1927 and 1939 Tatar was written with the version of the Latin alphabet shown below.
Cyrillic alphabet for Tatar (татар әлифбасы)
In 1939 the Cyrillic alphabet was imposed by Stalin. Stalin wanted to discourage contact between the Turkic republics and Turkey and worried about the development of alliances which might undermine the authority of the Soviet Union
Notes about Cyrillic Tatar:
2001 Latin alphabet for Tatar (tatar әlifbası)
In 2001 the authorities in Tatarstan decided to switch back to the modified version of Latin alphabet to write Tatar.