I would like to know the fatwa on a book called "the 99 beautiful names of allah" written by moulana mohammed idnees meerthi.
We do not know of this book and we have not read it so we cannot pass any comment on it. But the scholars, both classical and contemporary, have studied the ninety-nine names of Allaah that the Prophet (peace and blessings of Allaah be upon him) referred to when he said: “Allaah has ninety-nine names, one hundred less one; whoever memorizes them will enter Paradise.” Narrated by al-Bukhaari (2736) and Muslim (2677).
Many scholars have striven to derive the names of Allaah from the Qur’aan and Sunnah, and they have laid out guidelines by means of which they found out the names of Allaah, may He be exalted.
We should point out two things here:
1 – The scholars have defined these names of the basis of what each one of them thought was appropriate, and we cannot be certain that these are what the Messenger (peace and blessings of Allaah be upon him) meant.
2 – The hadeeth that is narrated by al-Tirmidhi in which these names are listed is da’eef (weak) according to the consensus of the scholars of hadeeth. You will find a more detailed discussion of this issue and others in the answer to question no. 72318.
And Allaah knows best.