story identification - Title of a book about a mysterious light in the sky from the late 90s?

In 1965, a mysterious beam of blue light came down from space and overlooked Northern California. This light had extraterrestrial powers that caused whomever the beam touched to die, go mad, or acquire a special unique power. This power is defined as full actualization of humankind, with strengths, understandings and communication abilities that exceed our normal capabilities. The people touched by the light in the novel were soon referred to as "Blues" and were segregated from society because of their new and improved super human powers. Soon after this discovery, they came together to try and find their purpose in the universe. As they look for their calling in life, an evil force, the "Gray Man", emerges, setting the stage for a battle later on in the novel between good and evil.