Stair models (different authors)
Childhood
Klein on the very first time in life
Freud was interested in the sexual development of the child.
Piaget for the child's cognitive development
Undom
Elkind has written about developments and challenges in the adolescens
All life
Erikson was interested in the whole of his life, his wife added a 9th phase
Kohlberg interested in moral development
Fowler interested in the development of faith
General development models
Maslow was interested in adults in particular, whom he graded