This document is an English-language abstract (approximately 1,500 words) of a monograph providing a comprehensive clinical, educational, and psychological study of children in special schools for the blind and poorly sighted. It summarizes investigations aimed at planning ways of differentiating teaching procedures for children with severe visual defects according to the state of their mental development. Ways of improving corrective training and medical treatment in special schools are considered. In the first chapter, the characteristics of the blind and poor-sighted are described, as well as their histories, giving clinical details for 4,680 blind and 511 poorly sighted children. The investigation revealed that 14.7% of children in schools for the blind were totally sightless, and the rest could be categorized in various degrees of poor sight. The second chapter discusses the main clinical forms of child blindness such as atrophy of the optic nerve, confenital cataract, trachoma, and congenital glaucoma. The third chapter covers the neurological features for the blind. The electrical activity of the cortex in terms of its sharp drop in blind children is explored in Chapter 4. Chapter 5 presents some observations on the development of cognitive activity in blind children. Chapter 6 features the mental development of blind children, and the last chapter discusses the difficulty of teaching language skills to blind children. (Author/GDB)