Quick and fun, chatty, non-academic--displays unnecessary erudition at times (e.g., at the first mention of any place name, Asimov typically notes anyone and anything of world historical importance connected therewith)--this text is basically the learned scientist's book report after reading seven translations of the Bible, plus a few commentaries & treatises on same.
The primary object of criticism is the geography, history, and linguistics of the biblical text--he does not get involved in doctrinal disputes, except to note that they existed, and to describe what might have been at stake historically (such as in the circumcision fights during the time of St. Paul). He doesn't present any scientific critique (noting only that the Bible miscalculates the value of pi in describing dimensions of Temple furniture)--but the scientific background of the writer is always present, insofar as miraculous and supernatural events are summarily dismissed as legends, metaphors, or other types of fictional accretions.
He doesn't footnote the views of other commentators, usually distinguishing them from his own views by marking others' theses as "some have said" or "the usual position." His own views on disputed issues appear to be marked out as tentative submissions, noting "perhaps" or "speculation." The non-academic style can be a bit frustrating in this respect.
He does give special attention to passages from the Hebrew scripture that later writers in the Roman period found compelling.
As an example of the awesomeness herein, consider Asimov's basic reading of the deuterocanonical text of Judith:
"This now adds an additional element of anachronism. We have the Assyria of the seventh century B.C. under the rule of Nebuchadnezzar of the sixth century B.C., which sends its army under a general of the fourth century B.C. to attack a re-established Judea of the fifth century B.C. Not a century is left out."
His opinion, for instance, on Judas Iscariot is interesting, too, as it adopts the contrarian thesis that "Iscariot" is not "man of Kerioth," a Judean designation (as distinguished from the other apostles, who were Galilean) but rather marks Judas as a member of the sicarii. Once Asimov elects a view, such as here, he runs with it, and the rest of his interpretation adheres thereto.
His reading of the Old Testament has definitely been influenced by higher criticism and other source studies--so we might consider his views in this regard to be serious; he certainly is pleased to point out dates of composition, interpolations, later amendments by editors, potential redactions, and so on in challenging the traditional theories of authorship. He's also keen on marking out purported prophecies that were actually written after the events they allege to predict, or errors in certain bona fide prophecies.
He has also spent time with the records of Egypt, Anatolia, Mesopotamia, Greece, Rome, and so on--or, at least, distillations of those records--in order to cross-examine the biblical account, which often enough is the only source for its allegations. He is honest enough to note when external records corroborate the biblical account, and seems to regard the biblical account as generally rooted in history, even if he wants to quibble with certain details, and dismisses the more fanciful material as not worthy of historicity.
Overall, interesting, lively, goes by much faster than one might foresee for 1200+ pages. Includes many maps, chronologies, indices, &c. It doesn't assume much in the way of familiarity with scripture--though he doesn't summarize all events in the text. A good example of the latter point is that his discussions of the Greek epistles is limited to the geographical and linguistics notes, with the points of doctrine only grossly mentioned, if at all. That should be considered a feature rather than a bug, of course.
Recommended for serious persons.