The curriculum for training physicists at Russian universities provides for a general course “History and Methodology of Physics”. The content of this manual, dedicated to the history of the emergence of atomic concepts, their development and current state, covers part of this course. The manual was prepared on the basis of lecture notes that the author gave for a number of years to physics students at the Peoples' Friendship University of Russia, and is an additional educational material for the author's course "Atomic Physics". The manual is intended primarily for physicists, but may be useful to specialists in related fields, as well as a wide range of readers interested in the problems of modern physics.