The paper is dedicated to the anniversary of Professor V. I. Puzik, Honored Science Worker. It gives the data of morphological studies from her dissertation and some sections of the dissertations supervised by V. I. Puzik. The paper also presents data on the diagnosis, clinical picture, and treatment of tuberculosis in adolescents. The problems of early detection, differential diagnosis, the significance of concomitant diseases and social factors in the course of tuberculosis are discussed. Emphasis is placed on the importance of drug resistance in adolescent patients with tuberculosis, which has been revealed in 63.3% of cases. Complex treatment with essential, reserve, and combined antituberculous drugs is recommended in relation to the sensitivity of Mycobacterium tuberculosis. It is also advisable to treat concomitant diseases and to prescribe pathogenetic agents enhancing the body's overall resistance.