The Qur’an is a record of the exact words revealed by Allah through the Angel Gabriel to Prophet Muhammad.  It was memorized by Muhammad and then dictated to his close companions and written down by the scribes, who cross-checked it during his lifetime. 

Not one word of the 114 chapters (Surahs) in it have been changed or tampered with over the past 1400 years since its revelation. 

Thus, the Qur’an in every detailed way, is the unique and miraculous text which was revealed to Prophet Muhammad over 14 centuries ago.

The Qur’an - the last revealed word of Allah - is the prime source for every Muslim’s faith and practice. It deals with all the subjects that concern us as human beings such as wisdom, doctrine, worship, etiquette, self-building, law and other subjects, however the basic theme is the relationship between God and His creations.

At the same time, it provides guidelines for a just society, proper human conduct and an equitable economic system.

Topics such as economics, social law and order, adoption, adultery, justice, charity, marriage, family life, divorce, laws of inheritance and other subjects are covered.

For example, regarding charity it has been mentioned:

“O’ you who believe! Do not make your charity worthless by reproach and injury, like him who spends his property to be seen by men and does not believe in Allah and the last day; so his parable is as the parable of a smooth rock with earth upon it, then a heavy rain falls upon it, so it leaves it bare; they shall not be able to gain anything of what they have earned; and Allah does not guide the unbelieving people.” (al-Qur’an, Chapter 2, Verse 264)

Regarding divorce, which although is permitted is Islam, is also one of the most detested acts is mentioned thus in the Qur’an:

“O’ Prophet (and believers), if you want to divorce your wives, you should divorce them at a time after which they can start their waiting period…Have fear of Allah, your Lord ... When their waiting period has ended, keep them or separate from them in goodness.  Let two just people witness the divorce and let them bear witness for the sake of Allah.  Thus does Allah command those who have faith in Him and the Day of Judgement.” (al-Qur’an,  Chapter 65, Verse 1-2)

Are there any Other Sources of Legislation?
Yes, the Sunnah - the practice and example of the Prophet Muhammad and his twelve immediate successors is the second authority for the Muslims. 

A Hadith is a reliably transmitted report of something that the Prophet (or his twelve immediate successors) did, said, or approved of.

Some examples of the Prophet's sayings are:

1. “No one is safe from sins unless he controls his/her tongue.”

2. “The listener of backbiting is the same as the backbiter.”

3. “Allah has fixed the livelihood of the destitute in the wealth of the rich. Consequently, whenever a destitute remains hungry it is because some rich people have denied them (their right).”

4. “The pleasure of Allah lies in the pleasure of one's parents and His wrath lies in their wrath.”

5. “Over indulgence of food causes various kinds of diseases.”

6. “Do not become obstinate since such a person will meet his destruction.”

Source: http://www.al-haqq.com/