The book by the outstanding Russian psychiatrist Viktor Khrisanfovich Kandinsky (1849-1889) is the first systematic study in the world medical and psychological literature of the phenomenon that later became known as "pseudohallucinations". First published in 1890, the work is based on both the doctor's clinical experience and the author's own experiences, who suffered from a severe endogenous mental disorder. Kandinsky proposed a clear distinction between true hallucinations and a special class of sensory and mental perceptions that, despite the absence of an external source, are perceived by the patient as actually occurring, but internally imposed, not belonging to his will. These experiences are accompanied by a feeling of violent intrusion into the sphere of subjective consciousness, loss of control over mental and affective activity, which makes them distinctive in the clinic of schizophrenic and paranoid psychoses. This publication presents not only a phenomenological description of pseudohallucinations, but also their classification, a discussion of the mechanisms of their occurrence, their connection with other psychopathological symptoms (ideas of influence, automatisms, speech disorders), as well as the first attempts to describe the structure of the so-called mental automatism. The conceptual apparatus proposed by Kandinsky formed the basis for the development of the later "Kandinsky-Clerambault syndrome" and is still used in psychiatric diagnostics. Despite the change in psychiatric terminology over the past hundred years, the book retains its methodological and clinical-descriptive value. It will be useful both for specialists in the field of psychiatry, clinical psychology and neuroscience, and for researchers of the history of psychiatry and the philosophy of consciousness. Presented for the first time in a modern academic design, Kandinsky's work opens up a unique opportunity for the reader to look into the world of impaired self-awareness not from the outside, but from the inside.