Answer
Salam (Peace) Curt,
Thank you for your question.
Thank you also for showing interest in knowing more about Islam and its divine Book, the Quran.
Please find part one of the answer to your question below. Find the second and final part at the link here.
First, we would like to invite you to take the time to read the Quran or at least listen to it. At this link, you will find the Quran available in different platforms. Just choose one of the options and you will enjoy a unique experience with the Quran.
Briefly, Islam is not a new invention or a new religion. Islam is the religion of all the prophets who came before Prophet Muhammad (peace be upon them all).
All the previous Prophets and Messengers came with one true message, i.e. to worship the One True God (Allah). Therefore, Islam is a continuation of the previous messages.
As you put it, all books have an audience and a message. The Book which contained the divine message of God is called the Quran.
The Quran was revealed to Prophet Muhammad via Arch Angel Gabriel over a period of 23 three years.
Muslims believes that the current Quran is the same Book that prophet Muhammad received over than 1430 years ago. No word was added, deleted, or changed in the Quran over this period of time. Muslims believe that the Quran will remain the same till the Day of Judgment.
Muslims also believe the hands of scribes and translators have touched the other Scriptures. Therefore, Muslims believe that the other Scriptures have been altered and distorted.
The Quran defines itself in the following verse:
{It is (the Quran) but a reminder to the worlds.} (Quran 38:87)
Allah the Almighty addresses Prophet Muhammad who received the Quran in the following manner:
{And We have not sent you, [O Muhammad], except as a mercy to the worlds.} (Quran 21:107)
Thus, the Quran is not for a specific group, nation, country, or people. The Quran is for all.
Also, The Quran is not for a certain time or place. The Quran is limitless. The message of the Quran is a universal message.
Allah says in the Quran:
{And We have not sent you except comprehensively to mankind as a bringer of good tidings and a warner. But most of the people do not know.} (Quran 34:28)
{Blessed is He who sent down the Criterion upon His Servant that he may be to the worlds a warner.} (Quran 25:1)
The Quran is unlike ideologies or ideas. The Quran does not belong to a certain category of the society.
When the Quran says, for example: {This is the Book about which there is no doubt, a guidance for those conscious of Allah.} (Quran 2:2), it means that those who follow its teachings will be the guided ones.
The Quran does not represent a certain class or defend its rights.
The Quran defines its message in the following verse:
{We have already sent Our messengers with clear evidences and sent down with them the Scripture and the balance that the people may maintain [their affairs] in justice.} (Quran 57:25)
Thus, the message of the Quran is to establish justice among all people.
Please continue reading part two at the link here.
And also please continue feeding your curiosity, and find more info in the following links:
https://aboutislam.net/reading-islam/my-journey-to-islam/logic-quran-led-islam/