“Another nutty conspiracy theory!” That’s what I first supposed as I started to read the manuscript Unmasking Columbus sent me just to edit its English. After all, it turned upside down most of what I had learned about Columbus since the 1940s.
It claimed that Columbus knew in October 1492 that he was nowhere near India, but that he called the Caribbean region he had reached “the Indies” in an outright lie, because he was a double agent actually serving the king of Portugal and double-crossing his patrons, Ferdinand and Isabella, that he was an expert geographer and navigator and a Portuguese nobleman, not a shipwrecked ignorant sailor or wool-weaver from Genoa.
I thought I would read a little of the book to enjoy myself poking holes in its arguments and then decline to edit it. However, the more I read, the more convincing its massive accumulation of historical details became. Far from fanatics, its authors present their claims modestly, pointing out areas that need further research, and even saying that their conclusions at present lack 100% proof. True, history rarely admits of 100% certitude, but I would say that their book provides the best answers to many previously unexplained problems in the Columbus puzzle.
I now believe that if Columbus were alive and on trial by any fair civil court, he would be found guilty of huge fraud carried out over two decades against his patrons.... Against my initial instinct, despite a lifetime that has taught me to question all things, I found myself believing that the case against Columbus presented here is about as solid as Fawn Brodie’s claims that Jefferson sired slaves by his Black slave Sally.... I refer you to two news clippings about my doctoral research at Columbia University, dealing with questions of authorship (to show that I am used to weighing evidence, evaluating sources, drawing conclusions from written remains). They are the New York Times, Sunday, August 6, 1961, pp. 1 (col. 2), 70 (col. 1) and Time magazine, August 18, 1961, pp. 43, 44.

What Manuel Rosa succeeded in doing was that which many Columbus historians until now had not been able to do or did not wish to do. He succeeded in proving the contradictions and falsities in the majority of the Columbus documents that, until now, the scientific community had accepted as good and correct. And at this point what that scientific community has to do is either accept the facts as pointed out by Manuel Rosa or prove with arguments why the documents that Mr. Rosa points out as being contradictory or false are really accurate and correct. What I am seeing here is a truth about Columbus that was maintained covered-up by the scientific community: mainly that the Genoese papers are either made-up or have nothing to do with Christopher Columbus’s true nationality. Therefore it remains an open question the true identity of Christopher Columbus and we must study Mr. Rosa’s proposition that Columbus was indeed a Portuguese nobleman. It is exactly by not having investigated this issue in the past that the Portuguese scientific community is seen today as having failed. There are others like Prof. Lorente doing Columbus DNA analysis and not one word from our own scientific community. How can they avoid being blamed if the Portuguese nationality ever becomes proven beyond a doubt? Only the will to continue investigating will tell if the version of the history put forth by Manuel Rosa, and others, about a Portuguese Colon is the correct history.
-- Fernando de Telde

It is not necessary to read a work to be able to criticize it, it is only necessary to know the subject through other works... And being that I am licensed in History... when I was loaned the book by  Mascarenhas Barreto on Columbus, I read it with pleasure... if someone will lend me  this new work about Christopher Columbus, having I the time I will read it with pleasure... at times a lot of old information, be it correct or incorrect, having been forgotten and then reused by whoever sees fit today must be pointed out here for the good of truth and justice.
- Português Racional author of the PH Colombina Blog

Dear Manuel da Silva Rosa, it was with great pleasure that I assisted the Columbus conference at the Geographic Society of Lisbon on 26th February 2007. Although I devoured your book there still remain many questions and themes left to be clarified. I would like to invite you to our university to do a conference for our professors and students about Christopher Columbus.
- Prof. Pedro Nevado, PhD, University Técnica de Lisboa (ISEG)

My congratulations on publishing the results of your 15-year investigation on Christopher Columbus's life. "The Mystery of Columbus Revealed" is an authentic "eye-opener" not only for the Portuguese but to Historians of other countries, languages and cultures. I hope soon this is published in the  major languages of the world... I am currently re-reading your book. Much of the details are better understood with a second reading, not because of a lack of clarity but due to the rich and immense quantity of information about Columbus that the book contains. In fact I feel that the multitude of Footnotes as well as the documents in the Appendix are almost as valuable as the text itself. Once more, my sincere congratulations to you, as well as to Mr. Eric J. Steele.
- Comendador José A. da Silva Campos, Order of Infante D. Henrique (1984). Agualva, Cacém, PORTUGAL