Thoughts to consider:
It is asserted by Islamic scholars and Western Academics that this is forgery, despite the acceptance and spreading of it among some groups of Muslims – and, Allah knows best each person’s intention.
As noted elsewhere: Hempher is not mentioned anywhere outside of this text as existing. No historical record can corroborate that Hempher existed and, as shown in the text of the book and the events reported within, it is highly questionable and likely a complete forgery. Western Academics have compared this text to The Protocols of the Elders of Zion as it likewise has a large readership but clearly has roots in forgery and become widespread with the agendas of certain groups. Regarding the so-called memoirs of Hempher / Hemphery:
On the first page Hempher says that the British Empire is vast, however the expansion of the British Empire to the mentioned areas (China, India, Middle East) did not occur until a century after this book is supposed to have been written. Hempher says that he met AbdulWahhab in Basra (Iraq) in 1712. At this time AbdulWahhab was 9 years old (born in 1703), and it is known that he did not travel to seek knowledge in Basra until 1722. Further chronological and dating discrepancies exist throughout, which have been reported in other larger critiques. Likewise, such a figure with such an important position and supposed affect on history, ought to have some link to historical record – however, there is absolutely no trace of him existing anywhere. In addition, there are no historical copies of this book. It emerges after a couple hundred years in complete form with unknown origins.
A question to consider: If the scholars of Islam and the academics of the West can find no evidence that this book is true, and it has been written by a non-Muslim, why are we taking it as truth and attacking our own Muslim brothers with it? Shall we not verify a claim before we spread it? Likewise, if we are to take knowledge (in particular if it is knowledge that attacks Muslims and the unity of the Ummah), shall we not take it from trustable scholarly sources?
And, Allah knows best.