Known for being the protege of Sigmund Freud, Jung has sometimes been lost in the modern discussion because he is so controversial. Surprisingly, near the end of his life he drifted away from a strict materialistic view of the world and from his writings one gets the sense that he was wrestling with some highly strange "random" life events that left him grasping for an explanation.
From these experiences, Jung incorporated the concept of synchronicities into his thoughts on the human psyche. He began noticing that the human mind seems to notice patterns between dreams, life events, and strange occurrences.
A prolific writer whose concepts can take years to grasp, a lot of people resort to reading things about Carl Jung, rather than just reading what he wrote. I highly recommend reading at least one of his books - slowly - to see the genius of this man.