The history of the establishment of the 'St. st. Cyril and Methodius' National Library is full of people and events that describe the building of the first cultural post Liberation institution in golden letters. For 143 years the Library of Bulgaria has been following the mission of the Bulgarian enlightenment by strengthening the national spirit and preserving the literary heritage. Since 1897, when the National Assembly passed a Legal deposit law for printed books in the national libraries, the activity of preserving and bibliographic registration of the state publishing production has been officially entrusted to the National Library in Sofia. On 28th November of the same year, the Library already had a statute and a temporary Library committee was elected and hired to settle and open the Library. The birthday of the National Library (in the new style) is 10th December. 20 years after the founding of the Library in Bulgaria, a Law on the Deposit of Printed Works in National Libraries was adopted, thanks to Konstantin Velichkov. For 143 years, library studies in our country have been a matter of honour for many intellectuals, enlighteners, men of the word, bibliographers and librarians. Since 1897, when the National Assembly passed a Legal deposit law for printed books in the national libraries, the activity of preserving and bibliographic registration of the state publishing production has been officially entrusted to the National Library in Sofia. Ref.: https://www.nationallibrary.bg/