Islamic failure series – Episode 22 – Hadith wasn’t supposed to be written down
Hadith can be defined as a collection of traditions containing sayings of the prophet Muhammad that, with accounts of his daily practice (the Sunna), constitute the major source of guidance for Muslims apart from the Quran
This Wikipedia link, written and maintained by Muslims,http://en.m.wikipedia.org/wiki/Hadith, is also an alternative link for you to verify, from which I quote the meaning of Hadith:
meaning the corpus of the reports of the teachings, deeds and sayings of the Islamic prophet Muhammad. The hadith literature was compiled from oral reports that were in circulation in society around the time of their compilation long after the death of Muhammad. Bukhari’s collection is considered the most reliable by many traditional religious scholars who are Sunnis. The Shi’as believe in an entirely separate body of Hadith
Hadith also has a grade or classification of correctness according to this Islamic-maintained Wikipedia link http://en.m.wikipedia.org/wiki/Hadith_terminologyfrom which I quote the definition of Sahih
Ṣaḥīḥ (صَحِيْح) is best translated as “authentic”.  Ibn Hajar defines a hadith that is ṣaḥīḥ lithatihi – “ṣaḥīḥ in and of itself” – as a singular narration (ahaad; see below) conveyed by a trustworthy, completely competent person, either in his ability to memorize or to preserve what he wrote, with a muttaṣil (“connected”) isnād (“chain of narration”) that contains neither a serious concealed flaw (ʻillah) nor irregularity (shādhdh). He then defines a hadith that is ṣaḥīḥ ligharihi – “ṣaḥīḥ due to external factors” – as a hadith “with something, such as numerous chains of narration, strengthening it.”
But in the Hadith itself, precisely this link which is Sahih, http://sunnah.com/muslim/55/92 Muhammad tells his people not to write down anything about him except for what was written about him in the Quran!
حَدَّثَنَا هَدَّابُ بْنُ خَالِدٍ الأَزْدِيُّ، حَدَّثَنَا هَمَّامٌ، عَنْ زَيْدِ بْنِ أَسْلَمَ، عَنْ عَطَاءِ بْنِ يَسَارٍ، عَنْ أَبِي سَعِيدٍ الْخُدْرِيِّ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ “ لاَ تَكْتُبُوا عَنِّي وَمَنْ كَتَبَ عَنِّي غَيْرَ الْقُرْآنِ فَلْيَمْحُهُ وَحَدِّثُوا عَنِّي وَلاَ حَرَجَ وَمَنْ كَذَبَ عَلَىَّ – قَالَ هَمَّامٌ أَحْسِبُهُ قَالَ – مُتَعَمِّدًا فَلْيَتَبَوَّأْ مَقْعَدَهُ مِنَ النَّارِ ”
Abu Sa’id Khudri reported that Allah’s Messenger (ﷺ) said: Do not take down anything from me, and he who took down anything from me except the Qur’an, he should efface that and narrate from me, for there is no harm in it and he who attributed any falsehood to me-and Hammam said: I think he also said:” deliberately” -he should in fact find his abode in the Hell-Fire
And what Muhammad asked not to do, Muslims wrote volumes about and became one of the official Islamic legislation and references to and about Islam.