The manual outlines the foundations of modern embryology from the standpoint of a systematic analysis of the stages of development of the human body at the earliest stages preceding birth. A detailed illustration in the drawings and explanatory comments of the author contributes to a deep study of the dynamics of the formation of all systems and organs in the process of human ontogenesis.The materials of the manual can be useful for understanding the causes of abnormal human development, including psychoverbal disorders. In particular, the manual will help the speech therapist find out the reasons for deviations in the development of speech from the norm, and in cases of violations that occurred during fetal development, build an individual program of corrective action that helps to overcome them.The manual is recommended for specialists in the child support system with disabilities, medical workers, psychologists, defectologists, speech therapists, as well as students and undergraduates studying at universities in this area of specialty.