There are 114 surahs in the Quran. Each surah is devoted to an overarching theme. Although the Quran was "revealed" to the Prophet Muhammad, beginning in 610, over a period of 23 years. In that chronology the Quran is reflective of specific historical incidents, anxieties, conflicts and epiphanies surrounding Muhammad's circumstances and early Muslim community. However, the Quran's surahs as they were written, arranged and essentially codified in their present order several decades after Muhammad's death aren't arranged in the same chronology as their order of revelation. Rather, they're arranged in descending order of length.
The last surahs--on daybreak, on onenes, on men, on help--are just a few verses long. The first surahs, far more devoted to signs than pragmatics ("The Exordium," "The Cow," "Women," "The Table," Cattle," "The Heights," and so on), are many pages long.
The surahs' division between the longer, more metaphorical section and the shorter, more pragmatic section is also reflective of Muhammad's early period in Mecca as opposed to his later period in medina, after the Hijra, or exodus, from Mecca in 622.
