Believing in all the Messengers and Prophets - form Adam to Muhammad - may peace be upon them all, is one of the pillars of faith in Islam. Denying any of them is a form of kufr - disbelief - which if not repented leads to Hell-fire. Similar is the case with exaggerating any of them beyond their respective honorable status that Allah, the All-Mighty, has given them, as the followers of many faith are doing.
(The Messenger believes in what has been revealed to him from his Lord, as do the believers. Each one (of them) believes in Allah, His Angels, His books, and His Messengers. "We make no distinction between any of His messengers." And they say, "We hear and we obey. [We seek] Your forgiveness, our Lord, and to You is the [final] destination.) [Qur'an 2:285]
(We do relate to you (O' Muhammad) the best of stories in what We have related to you the Qur'an, although you were, before it, among the unaware.) [Qur'an 12:3]
(So relate the stories that perhaps they will give thought) [Qur'an 7:176]
The book is thus unique in its content, dealing with the important events of the Prophets and Messengers with all authentically right from Adam the first prophet to Jesus, Peace be upon them all. As for Prophet Muhammad, the author has written a separate book about his seerah.