God's Chinese Son is the first thing that comes to mind. The story focuses on the spread of Christianity through China led by Hong Xiuquan, who believed that he was the brother of Jesus Christ. The government tried to quash their efforts, viewing Christianity as a threat to Chinese society and social order.

It's not an easy read, but it is definitely enlightening.

Sorry for the late comment and I hope you haven't stopped looking into the Taiping – it's one of the most criminally insufficiently covered periods IMO. I have read the following:

• God's Chinese Son (1996) by Jonathan Spence – Good general overview from the inside of the Taiping and contextualises the cultural climate well.
• Autumn in the Heavenly Kingdom (2012) by Stephen Platt – Places the later years of the Taiping in a global context, considering British, French and American involvement as well as the effect of the US Civil War.
• The Taiping Heavenly Kingdom: Rebellion and the Blasphemy of Empire (2005) by Thomas H. Reilly – Quite explicitly purely focussed on the religious angle. A couple of reviews understandably accuse it of preconceived biases, so be warned.
• Chinese Sources on the Taiping Rebellion (1963) by James C. Cheng – A nice variety of translated original sources, each covering a particular aspect or period. Far from a comprehensive look at all the 1000+ original documents, but offering glimpses into the perspectives of the two sides.

I have not read the following but have copies in the post as I write this:

• Ti-Ping Tien Kuoh, or the History of the Ti-Ping Rebellion (1866) by Augustus Lindley – Written by a volunteer fighter in the Taiping army with a serious beef with Chinese Gordon. Gives interesting contemporary attitudes, especially because the British public at the time of publication shared severe outrage at Qing atrocities that British intervention had tacitly condoned.
• The Taiping Rebellion: History and Documents (1966-71) by Franz H. Michael and Chang Chongli (3 volumes) – 1 volume of history and 2 of documents on the Taiping, all in English. The 1st (History) volume is quite short but the Documents volumes are basically standard compendia of Taiping writing even now.

I want to read but have yet to procure due to the fact that it is out of print and so now costs an arm and a leg:

• The Taiping Revolutionary Movement (1973) by Jian Youwen (or Jen Yu-wen) – Probably the most comprehensive modern monograph on the Taiping ever written, by a leading scholar of the movement with access to many original documents and artefacts until the rather inconvenient outbreak of WW2 and the Communist takeover.

I'd recommend starting out with Volume 1 of Michael & Chang to see if it interests you, then Spence, Platt and Reilly in that order. I may revise my opinion depending on what I think of Lindley and/or Jian, but as of writing that's my recommendation.