SOURCES of general information about intelligence testing are given in Pintner's annual summaries (87) which cover theories, new tests and texts, and results of studies and investigations. A comprehensive bibliography has been prepared by Hildreth (45). General texts on intelligence and its measurement are offered by Boynton (14), by Garrett and Schneck (34), and a second edition in 1931 by Pintner (86).This chapter will review the nature of intelligence in its general and special aspects; the clinical interpretation of functions; mental growth and changes; test standardization and variability; new tests; and suggested topics for further research.