Ibn Ishaq - Wikipedia, the free encyclopedia
Ibn Isḥaq wrote several works, none of which survive. His collection of traditions about the life of Muhammad survives mainly in two sources:
an edited copy, or recension, of his work by his student al-Bakka'i, as further edited by Ibn Hisham. Al-Bakka'i's work has perished and only Ibn Hisham's has survived, in copies. (Donner 1998, p. 132)
an edited copy, or recension, prepared by his student Salamah ibn Fadl al-Ansari. This also has perished, and survives only in the copious extracts to be found in the volumimous historian al-Tabari's. (Donner 1998, p. 132)
fragments of several other recensions. Guillaume lists them on p. xxx of his preface, but regards most of them as so fragmentary as to be of little worth.
According to Donner, the material in Ibn Hisham and al-Tabari is "virtually the same". (Donner 1998, p. 132) However, there is some material to be found in al-Tabari that was not preserved by Ibn Hisham. The notorious tradition of the Satanic Verses, in which Muhammad is said to have added his own words to the text of the Qur'an as dictated by a jinn is found only in al-Tabari but Tabari was a collector of all reports regardless of its validity.
The English-language edition of Ibn Ishaq currently used by non-Arabic speakers is the 1955 version by Alfred Guillaume. Guillaume combined Ibn Hisham and those materials in al-Tabari cited as Ibn Isḥaq's whenever they differed or added to Ibn Hisham, believing that in so doing he was restoring a lost work. The extracts from al-Tabari are clearly marked, although sometimes it is difficult to distinguish them from the main text (only a capital "T" is used).
Things that you call out of harmony with the Quran are do entirely with your own personal failure to understand the Quran.
For those interested in the details of the satanic verse and the hijra
Prophet of Doom - Islam in Muhammadâs Own Words - 10 - Muddled Message
Prophet of Doom - Islam in Muhammadâs Own Words - 11 - Satanâs Bargain