The document summarizes the four yugas in Hinduism - Satya Yuga, Treta Yuga, Dwapara Yuga, and Kali Yuga. It explains that a yuga is a period of 100,000 years and together they make up a Kalpa or cycle of yugas. It provides details about each yuga, including which avatars arrived in each one. For example, it states that Satya Yuga was the golden age when the first four avatars came, while Kali Yuga is the current iron age when the 10th avatar Kalki will arrive.