The Hindu-Arabic Numerals by David Eugene Smith and Louis Charles Karpinski
attempts to trace the origin of our present numbers from either the Arabs, the Hindus, or the Chinese. David E. Smith collects much of the, then known, sources for the early development in a thin scholarly tome. This is a reprint of the 1911 book.
In terms of writing, the book is, as one would expect from a 19th-century educated scholar, written with care, without flowery sentences, and with appropriate footnotes. (One note -- Smith does assume a working knowledge of Latin, French, and German and is happy to quote long passages in these languages mainly in his footnotes.) Smith has included many reproductions of early numbers and references to texts, both printed and manuscript, to justify his conclusions. Anyone wishing to study the history of numbers could easily draw up a long reading list from his footnotes. This is THE book to start with, if one wants a scholarly treatment.
There were two 'problems' I had with this book. First, it was published in 1911, so much of the secondary material referred to was published in the 1890's or earlier. I do wonder what, if any, new work has been done in this field.
Second, I had assumed that this book would trace the Hindu-Arabic numerals from their origin to their present form. Smith does as good a job as can be done in defending his theory of their origin. He traces the numerals to about the 12th century and then skims over any later development. I understand that history from the 13th century onward is a bit out of his normal period, but I was hoping of a bit better treatment.
Overall, this is a great starting point for studying where the numerals we use came from. I wish I had read this several years ago!