Complex sentence: In 1955 he obtained a master's degree, and in 1958 an Ed.D, from the Teachers College, Columbia University, and in 1959 he started teaching at New York University (NYU).
Split into simpler sentences: In 1955 he obtained a master's degree, and in 1958 an Ed.D, from the Teachers College, Columbia University. In 1959 he started teaching at New York University (NYU).