The study is in three parts. Part One looks at background. It briefly covers historical concepts of education; it goes on to look at the people who enter teaching and why they have chosen it as a career. Lastly part one looks at the hurdles they have to negotiate before being offered a place a college of education. Part Two looks at some of the variables which affect student teaching performance – personality, flexibility and how these have been shown to relate to measured teaching performance. It also looks at those variables external to the student which research has shown are likely to affect the marks a student will get for teaching practice. Finally section two looks at the relationship between teaching practice performance and future performance as a qualified teacher. Part Three is the empirical research. Five year groups of students already in colleges of education and one further group interviewed for a place at Bede College, Durham, constitute the research sample. Measures of academic performance, interview grades, I.Q. and flexibility scores were used as predictors of student teaching marks. Consistently the I.Q. score and flexibility score in multiple battery produced the best first order multiple prediction of teaching practice marks. Also consistently, G.C.E. and Interview grades produced the worst multiple prediction of teaching practice marks. The test of flexibility was shown by multiple regression analysis to consistently provide the significant predictive contribution to those multiple batteries in which it was present. The women students obtained very significantly higher scores on the test of flexibility than did the men students. One unexpected finding was that students who would have preferred to go to university were regarded as significantly poorer ' classroom performers than the rest. The appendices deal with the various predictors used in the empirical study, in particular with the development of the test of flexibility. The hypothesis that a test of verbal flexibility would predict the marks awarded to students for their teaching practice performance was accepted