Surah Ya-Seen (Arabic: سورة يس) is the 36th 'chapter' of the Qur'an with 83 ayat, and was revealed in the holy city of Makkah. It is considered the Heart of the Qur'an.
This sura is normally read by Muslims when somebody passes away.
The Surah talks about a city of disbelivers to whom Allah sent 2 messengers, yet they didn't believe in them and so God sent them a third one. But the disbelievers even rejected him and said that the messengers were fake and god has sent down no messngers. The disblievers also called the messengers, a bad omen. But then a old man from the disbelievers urges his people to follow the messengers for they are indeed real and he now knows the straight path and has been forgiven by god.
The Sura also mentions how the believers will enjoy their life in heaven and how the disbelievers will be punished in hell for they have not believed in the true god and the straight path.
It is also revealed in this Sura that Allah has not thought his messenger(Muhammad), poetry, but plain Quran.
The Surah concludes by describing some of Allah's wonders, like the creations of Earth and heaven and how he can do it again, and how man was created by him and shall return to him.