This chapter deals with both sides of the aging process which carries losses and
gains, growth and decline. First, the biology of aging is examined as a determinant
of individual and psychosocial decline and impairment. Second, relationships and
transactions between the individual and his/her socio-cultural context are going
to be described in several psychological characteristics such as cognitive plasticity,
positive and negative emotions and coping styles. Thirdly, the importance of
the individual as an agent of his/her aging process is emphasized, and ends by
positing a broad multidimensional-multilevel aging model. Finally, limitations of
the aging process coming from images and beliefs about the aging process are
described before introducing some conclusions and remarks.