This book should not be called "a documentary history." It is true that it consists of documents (exclusively so, excepts for a very basic introduction) and that these are historical, but the professed conjunction does not obtain. The book prides itself in being non-interpretative, but the problem is that no more than a dozen pages are needed for an exhaustive, non-interpretative history of the Galileo affair. It becomes a 400-page book only by being extremely repetitive. Every single point is repeated at least three or four times: first in a letter or two, then in some treatise, then in Inquisition commission reports, then in witness testimonies before the Inquisition, then in the Inquisition's conclusion, etc.
What this book is not may be illustrated with an example from the short introduction. Here we read that Pope Urban VIII, whose tolerance Galileo overestimated, may have been driven to make an example out of Galileo to mend his own reputation, especially in relation to critiques of his not being ardent enough in his support for the catholic side in the thirty years war. One may have hoped that pursuing letters and internal documents would reveal precisely this type of behind-the-scenes aspects of the affair. But unfortunately the letters are far more formulaic and no more revealing than the formal proceedings themselves. The final Inquisition report of about five pages is in effect a concise summary of the whole book; the rest is almost entirely redundant reiteration.
The outline of the story, to which so very little depth is added, may be recounted as follows.
The dispute seems to have been sparked not so much by heliocentrism as such but rather by Galileo's forays into scriptural interpretation. Galileo claims that in such matters "one must begin not with the authority of scriptural passages but with sensory experience and necessary demonstrations" (p. 93). This because "Scripture appear to be full not only of contradictions but also of serious heresies and blasphemies; for one would have to attribute to God feet, hands, eyes, and bodily sensations, as well as human feelings like anger contrition, and hatred, and such conditions as the forgetfulness of things past and the ignorance of future ones" (an argument which, by the way, we hear him repeat three times; pp. 50, 85, 92). The clash with the interpretations of the church fathers Galileo explains by the fact that heliocentrism was not an issue at that time (p. 108) and that such matters were considered unimportant. He quotes St. Augustine as saying that "God did not want to teach men these things which are of no use to salvation," and ask how, then, "one can now say that to hold this rather than that proposition on this topic is so important that one is a principle of faith and one is erroneous?" (p. 95). As for actual biblical interpretation, Galileo's most prominent example is that of Joshua stopping the sun to lengthen the day. Galileo criticises the geocentric interpretation by distinguishing the "Prime Mobile" daily motion of the heavens and the annual motion of the sun along the zodiac: stopping the latter would not lengthen the day but rather shorten it. He offers instead a Copernican interpretation which is based on the assumption that the sun's rotation causes all motion, so that stopping it would stop the entire solar system. (Pp. 53-54.)
It seems that it was primarily this provocation that brought the matter to the Inquisition's attention (pp. 134-135, 138). Once provoked, the Inquisition also moved to condemn holding heliocentrism as physical truth. Perhaps they did so only because of the theory's proponents' explicit polemic with the church. After all, Copernicus' book had long been permitted, and Galileo's own Letters on Sunspots of 1613 had been censored only where it referred to scripture, not where it asserted heliocentrism.
The outcomes of the first Inquisition proceedings (1615-1616) were: a condemnation of heliocentrism as "formally heretical" (p. 146); a special injunction that Galileo must not "hold, teach or defend it in any way whatever" (p. 147); mild censoring of Copernicus' book (viz., removal of a passage concerning the conflict with the Bible and a handful expressions which insinuated the physical truth of the theory; pp. 149, 200-202). Thus Galileo was not actually convicted, and to protect himself from slander he requested a certificate of this fact from Cardinal Bellarmine (p. 153).
Galileo did indeed keep quiet for a number of years, but he was lured out of silence, it seems, by a false sense of security stemming from his good relations with the new Pope, Urban VIII (cf. p. 155), in light of which he "artfully and cunningly extorted" (in the words of the Inquisition, p. 290) a permission to publish the Dialogue on the Two Wold Systems in 1632.
A special commission appointed by the Pope found many inappropriate things in the Dialogue, but this was not a major issue, they noted, for such things "could be emended if the book were judged to have some utility which would warrant such a favor" (p. 222). The problem was instead that Galileo "may have overstepped his instructions" not to treat heliocentricism (p. 219). This is an internal document so presumably it is sincere. The same report also points out that Galileo had placed the Pope's favourite argument (that the omnipotent God could have created any universe, including a heliocentric one), which he had been asked to include, "in the mouth of a fool" (p. 221).
This forced the second Inquisition proceedings in 1633. Galileo's defence was quite pathetic and transparently dishonest. He claimed that: in the Dialogue "I show the contrary of Copernicus's opinion, and that Copernicus's reasons are invalid and inconclusive" (p. 262); in light of the accusations, "it dawned on me to reread my printed Dialogue," and to his surprise "I found it almost a new book by another author" (pp. 277-278); he did not recall the injunction's phrases "to teach" or "any way whatever" since these did not appear in Bellarmine's certificate, "which I relied upon and kept as a reminder" (p. 260). Of course he was forced to abjure. The Dialogue was prohibited, but not for its contents but rather, in the words of the Inquisition's sentence, "so that this serious and pernicious error and transgression of yours does not remain completely unpunished" and as "an example for others to abstain from similar crimes" (p. 291).