Darkness in my head: Why do we get depressed and how do we find hope?

We are all human, and we all have worries and problems, there is no person on the face of the earth who has not gone through times of despair and frustration, when they hated themselves, the world, and the people around them.. but we confuse depression as a disease with frustration, sadness, and distress, so if you are frustrated from a difficult situation you went through, or sad about missing an important opportunity or losing a loved one; this does not necessarily mean you are depressed. Depression is something different, it has a different story, and sometimes it chooses specific people without others to attack them, which makes them and those around them wonder: Is there a treatment for depression? Can it be cured? How do we protect ourselves from getting it? How can we get out of any state of sadness or distress we are going through? In your hands now is a book that will not only be useful for the depressed, but beneficial for everyone who reads it. Darkness in my head.