All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
The book entitled Al-Ghunyah is written by Shaykh ‘Abdul Qaadir Al-Jeelaani and the name of the book is "Al-Ghunyah li taalibi tareeq Al-Haq ‘azza-wajal”.
The former and contemporary scholars always attributed the book to Shaykh Abdul Qadir and they quoted from it.
Ibn Katheer said in his book Al-Bidaayah wan-nihaayah about him:
“He was righteous and Allah-fearing, and he authored the book Al-Ghunyah and the book Futooh Al-Ghayb, which included good things, but he mentioned in them inauthentic and fabricated Ahadeeth. In general, he was among the prominent Shaykhs.” [End of quote]
Shaykh Ibn Taymiyyah also attributed this book to him and quoted from it many times.
As for your question about Ghunyatu At-Taalibeen, then we do not know exactly which book you are referring to, because there are many books which have this title.
For more benefit, please refer to Fatwa 86238.
Allah knows best.