(salam)
I heard a lot about Al Ghadir. It's said that it's a masterpiece of Allama Abd al Hussain al Amini, the scholar who spent his life searching for knowledge to write an irrefutable and comprehensive book proving the authenticity and Shia Muslim perspective of the famous Hadith of Pond of Khumm. Many debaters recommended this book to their readers. Thus, I started reading it. It was actually written in Arabic and translated it Persian. Then a scholar from India, Sha'ur of Gopalpur, converted the entire book in Urdu.
Al Amini first proved that Hadith of Pond of Khumm is an agreed and authentic hadith. Then he proved that the Prophet ((صلى الله عليه وآله وسلم)) was actually declaring the status of Imam Ali (عليه السلام) as his successor. He also referred to those Shia Muslim poets who had used the Hadith of Pond of Khumm as an evidence of superiority of Imam Ali and Al Amini quoted them. He also criticized the Caliphs, Muawiya and other Sunni Muslim scholars and provided references from their own books.
I spent months reading it and finished it just now a few minutes ago.
http://www.ziyaraat.net/findbook.asp?Escritor=Allama+Abdul+Hussain+al-Amini&Tema=All&orderby=titulo&idioma=All&srchwhat=All&submit=+Find+Books+