People of the Books are the Jews and Nazareans.
The Jews have Torah, sent to Prophet Moses (pbuh).
The Christians claimed to have Bibles which was from Prophet Jesus (pbuh). However, the Bible is not the holy book meant by God, it was the Injeel (Gospel), and it does not have Trinity doctrine or any deviancy practiced by Christians today. Even the name Christianity is not mentioned anywhere in the Bible nor Gospel.
The problem with the People of the Book began when they refused to acknowledge Muhammad (pbuh) as the last Prophet sent to mankind as Messenger of God.
Jews refused Muhammad because he was not a Jew, he was Arab and he started from amongst the Arabs and the metropolitan city of Medina and Mecca. There were Jews in these cities but because of their own faults and bad deeds, they were expelled. Just because Muhammad was an Arab that Jews refused even though it is clear in their book about the characteristics of the Last Prophet ! And Jews are quick to label anybody else as `anti-Semite' - Arabs are Semites too, descendent of Ishmael and Abraham. Jews are descendants of Israel and Abraham (peace be upon them).
During the time of Prophets Moses and Aaron (pbut) the Jews were divided into two - those loyal to God and the Prophets, and those who constantly breached the laws and committed excesses, transgressed and did mischiefs. Usury and idolatry, sorcery, lies and deceptions. And the rabbis took the Talmud to replace Torah (the holy book), and wrote many strange and evil teachings in the Talmud adhered by Jews (Judaism) until today. The reason for Zionism and Israeli atrocities are motivated by Talmudic teachings.
The Christians on the other hand, took Prophet Jesus (pbuh) as the God, or Son of God, they invented Trinity out of nothing!
As Muslims, we are required to call them `Kaafir' for their disbelief in Islaam, Muhammad, the Quraan, and for their hatred and enmity towards Islam.
Even though Jews as you can see on TV are very religious with their own peculiar dresses and their form of prayers, they regard God as `employer' who can be slandered, and they invent things and claim it is God's commands, for example, the state of Israel. And Zionism is the worst product of Jewry.
Christians are transgressing by associating God with His Creator, by saying Prophet Jesus is son of God, and by worshipping Jesus, and take the cross as their point of worship.
But please know that God is the Most Knowing, and Wise - He will accept the repentance of Jews and Christians if they discard their deviancy and truthfully embrace Islaam and become devoted Muslims.
If you are really interested in Islaam, then don't let the Jewish rabbis and Christian priests and evangelists mess with your mind any longer or stop you from the straight Path. The Muslims of the world welcome you with open arm, and we are ready to protect your honor and assist you in any possible way.
The excerpt from the Quraan below, is meant to the Jews and Christians
In the Name of Allah, the Most Gracious and the Most Merciful
[5.68] Say: 'People of the Book, you are not upon anything until you establish the Torah and the Gospel and that which is sent down to you from your Lord.'
And that which is sent down to you (the Quraan to Prophet Muhammad) from your Lord will surely increase the tyranny and disbelief of many of them. But do not grieve for the unbelieving nation.
[5.69] Those who believe, Jews, Sabaeans, and Nazarenes - whoever believes in Allah and the Last Day and does good shall neither fear, nor shall they sorrow (as long as they do not reject any of the prophets).
[5.70] We took a covenant with the Children of Israel and sent forth Messengers to them.
But whenever a Messenger came to them with that which did not suit their fancies they belied some and killed others.
[5.71] They thought there would be no trial; so they were blind and deaf. Then Allah turned towards them; then again many of them were blind and deaf. And Allah is the Seer of what they do.
[5.72] The unbelievers are those who say: 'Allah is the Messiah, the son of Mary .'
But the Messiah said: 'Children of Israel, worship Allah, my Lord and your Lord.'
He who associates anything with Allah, Allah has indeed forbidden Paradise to him, and his abode shall be in the Fire. The harmdoers shall have no helpers.
[5.73] Indeed those who say: 'Allah is the third of the Trinity ’ became unbelievers.
There is but One God. If they do not desist in what they say, a painful punishment will afflict those of them that disbelieve.
[5.74] Will they not turn to Allah in repentance and ask His forgiveness? He is Forgiving, Merciful.
[5.75] The Messiah, the son of Mary, was not except a Messenger, other Messengers had gone before him. His mother was in the state of sincerity, they both ate food.
See how We make plain to them Our signs. Then, see how perverted they are.
[5.76] Say: 'Will you worship instead of Allah that which owns neither harm, nor benefit for you? Allah is the Hearer, Knower.'
[5.77] Say: 'People of the Book! Do not exaggerate your religion, other than the truth, and do not follow the desires of a people who went astray before, and led many astray, and, (once again) have gone astray from the Straight Path.'
[5.78] Those who disbelieved of the Children of Israel were cursed by the tongue of (Prophets) David and Jesus, the son of Mary, because they disobeyed and transgressed.
[5.79] They did not forbid one another from the wrongdoing they were committing. Evil is what they were doing.
[5.80] You see many of them taking the unbelievers as guides. Evil is that to which their souls forwarded them, that Allah is angered against them, and in the punishment they shall live for ever.
[5.81] Had they believed in Allah and the Prophet (Muhammad) and that which is sent down to him, they would not have taken them (unbelievers) as guides. But many of them are evildoers.
[5.82] You will find that the most people in enmity to the believers are the Jews and idolaters, and that the nearest in affection to the believers are those who say: 'We are Nazarenes.' That is because amongst them there are priests and monks; and because they are not proud.
[5.83] When they listen to that which was sent down to the Messenger, you will see their eyes fill with tears as they recognize its truth. They say: 'Lord, we believe. Write us among the witnesses.
[5.84] Why should we not believe in Allah and in the truth that has come down to us? Why should we not hope for admission among the righteous?'
[5.85] For their words Allah has rewarded them with Gardens underneath which rivers flow, where they shall live for ever. Such is the recompense of the righteous.
[5.86] But those who disbelieve and belie Our verses shall be the companions of Hell.
[61.5] And when Moses, said to his nation: 'Why do you harm me, when you know that I am the Messenger of Allah sent to you?' But when they swerved away Allah caused their hearts to swerve. Allah never guides impious people.
[61.6] And when (Prophet) Jesus, the son of Mary said: 'Children of Israel, I am sent to you by Allah to confirm the Torah that was before me, and to give news of a Messenger (Prophet Muhammad) who will come after me whose name shall be Ahmad (Paraclete, Perekleitos).'
Yet when he came to them with clear proofs, they said: 'This is clear sorcery.'
[61.7] And who does greater evil than he who forges a lie against Allah, when he is being called to Islam? Allah does not guide the harm-doing people.
[61.8] They seek to extinguish the Light of Allah with their mouths; but Allah will complete His Light, much as the unbelievers dislike it.
[61.9] It is He who has sent His Messenger with guidance and the Religion of Truth, so that He raises it above all religions, much as the unbelievers dislike it.
[61.14] Believers, be the helpers of Allah. When (Prophet) Jesus, the son of Mary said to the disciples: 'Who will be my helpers unto Allah?' The disciples replied: 'We will be the helpers of Allah.' A party of the Children of Israel believed, and a party disbelieved. So, We supported those who believed against their enemy, and they overcame.
[4.171] People of the Book, do not exaggerate your religion. Do not say about Allah except the truth.
Indeed, the Messiah, Jesus son of Mary, is only a Messenger (and Prophet) of Allah, and His Word (Be) which He gave to Mary, and a (created) spirit by Him. So believe in Allah and His Messengers and do not say: 'Trinity.'
Refrain, it is better for you. Allah is only One God. Exaltations to Him that He should have son!
To Him belongs all that is in the heavens and in the earth, it is sufficient that Allah is the Guardian.
[4.172] The Messiah would not despise being a worshipper of Allah, nor would the angels who are near. Whosoever despises worshipping Him, and becomes proud, He will surely assemble them all to Him.
[4.173] As for those who believe and did good deeds, He will pay them in full their wages, and He will increase them from His Bounty. As for those who despise and became proud, He will punish them with a painful punishment, and they will find neither a guide nor a helper for themselves, other than Allah.
[2.130] And who has no desire for the religion of Abraham, except he who fooled himself? We chose him in this world, and in the Everlasting world, he shall be among the righteous.
[2.131] When his Lord said to him: 'Submit,' he answered: 'I have submitted to the Lord of the Worlds.'
[2.132] Abraham charged his children with this, and so did Jacob, saying: 'My sons, Allah has chosen for you the religion. Do not die except being submissive (Muslims).'
[2.133] Or, were you witnesses when death came to Jacob! He said to his children: 'What will you worship after me?' They replied: 'We will worship your God and the God of your forefathers, Abraham, Ishmael, and Isaac, the One God. To Him, we are submissive.'
[2.134] That was a nation that has passed away. Theirs is what they earned, and yours what you have earned. You shall not be questioned about what they did.
[2.135] They say: 'Be Jews or Nazarenes and you shall be guided.' Say: 'No, rather the Creed of Abraham, the upright one. He was not among the idolaters.'
[2.136] Say: 'We believe in Allah and that which is sent down to us, and in what was sent down to Abraham, Ishmael, Isaac, Jacob, and the tribes; to Moses and Jesus and the Prophets from their Lord. We do not differentiate between any of them, and to Him we are submissive (Muslims).'
[2.137] If they believe as you have believed they shall be guided; if they reject it, they shall surely be in clear dissension. Allah will suffice you. He is the Hearer, the Knower.
[2.138] The (indelible) marking of Allah. And who marks better than Allah! And for Him we are worshippers.
[2.139] Say: 'Would you dispute with us about Allah, who is our Lord and your Lord? Our deeds belong to us and your deeds belong to you. We are sincere to Him.'
[2.140] Or do you say that Abraham, Ishmael, Isaac, Jacob, and the tribes, were Jews or Nazarenes!
Say: 'Who knows better, you or Allah? Who is more unjust than he who hides a testimony received from Allah? And Allah is not inattentive of what you do.'