The Authorized Copy
This manuscript contains the first two books of Mishneh Torah by Maimonides. It is famous because, towards the end of the manuscript, Maimonides himself wrote a note declaring that this manuscript was corrected against his own personal copy of Mishneh Torah. Therefore, it must reflect a very accurate version of the book.
Without getting here into the polemics that sprung up around this manuscript a few decades ago, I would like to mention that in a recent article, Karmiel Cohen has demonstrated that this manuscript does not always reflect the final stage of Mishneh Torah. There are instances where R Abraham Maimonides testifies that his father changed his mind and corrected the text, and this correction is not reflected in the Huntington manuscript. But, on the whole, it is definitely a manuscript worthy of a great deal of attention.