3. Early adulthood (17-45): characterized by greatest energy and abundance and likewise by greatest contradiction and stress. This is the era of drive, ambition, obligations, and attempts to succeed in all areas of life. Whilst potentially fulfilling, it can also provide enormous bouts of stress.

4. Midlife Transition (40-45): Levinson (in sync with Jung, Erickson, and Ortega) sees this era as constituting a sharp break between early adulthood and middle adulthood manifested by greater focus on others as opposed to self and by a more humane and reflective temperament and perspective.

5. Middle adulthood (40-65): Our biological capacities are somewhat weakened. Our focus transfers from ourselves to others, and we feel a responsibility for the future generation.

6. Late Adult transition (60 +) is a synthesis and linkage of both middle and late adulthood

Levinson defines "life structure" as consisting of the individual's relationship to significant...

Similarly, too, Levinson observed an orderly progression consistent with life's stages. The sequence, he noted, was dialectical in that it consisted of alternating structure building with structure-changing (transitional) periods. A structure-building period ordinarily lasts 5 to 7 years, whilst the transitional period abruptly terminates the existing life structure, and creates the possibility for a new one. Here come crucial choices and commitments that then determine the next step. In this way, Levinson's theory is similar to that of Erickson's in that Erickson, too, propounds satisfaction of stage level before successfully transitioning to next.
Finally, Levinson suggests that it is imperative to make key choices, form a structure around these choices, and to pursue values and goals. One's key choices are imperative…