In Dreams From My Father, what impact does his father's absence have on Obama's life? How does he cope with this, or fail to?

Because Barack Obama is of mixed race origin, the absence
of his Kenyan father throughout most of his life caused him to have something of an
identity crisis.  That is, he knew he had a Kenyan family and heritage, but had no
connection to that side of his culture while he was growing up.  He substituted the male
role model with his Grandfather, who he speaks of in glowing and affectionate terms
throughout this book.

He still wandered a bit when he was a
teenager, experimented with drug use, and got involved in other negative activities.  He
attempts to adopt some Indonesian culture as well during his time livign there with his
mother and stepfather.  All of these were coping mechanisms and strategies that didn't
really help all that much until he spent some time with his father, and traveled to
Kenya to meet his extended family.