At the monkeys' current age, the only history they'll be getting for a while is in narrative form. Bible stories, stories of famous people, stories of ordinary people living in different times, etc. But at a certain point (perhaps around age 8-10) a child moves from simply reading stories to needing to learn about world, national and local history in a larger narrative framework. At this point, the student begins reading that most dangerous of academic creations: the survey text. The scylla and charybdis of the survey text genre are boredom and simplification to the point of falsehood. (Or perhaps the metaphor is inapt, since many survey texts are both boring and overly simplified.)
The danger, of course, is that a survey text seeks to smooth over the questions left open by lack of sources or contradictory sources by providing the student with a single narrative through which to understand the history of a period. An author with a bias may leave out or completely distort the meaning of a event or period. (I've seen survey texts which insist the primary motivation of the crusades was an economic need to set up client states for trade.) On the other hand, a survey text is sometimes so tentative that it doesn't provide any coherent narrative, or gets bogged down in facts that provide the student with trivia, but not a general understanding of the period.
The life of Christ and the origins of the Church are one period on which many have an opinion (and also cover an intersection of history and doctrine which many secular writers feel uncomfortable with and many religious writers have strong opinions about) and so it seems a particularly sticky problem. On the one extreme, there are books like Ann Carroll's Christ the King, Lord of History, which takes as its central premise that the incarnation is the central event against which all historical events should be contextualized. On the other extreme, many texts make it sound as if Christianity was invented by Constantine, or was indistinguishable from the various pagan mystery cults that abounded from the first century BC through the second century AD.
On a side note, I think people should be a little more ambitious about the age groups the recommend a book to. Christ the King, Lord of History is recommended for grades 11-12, but the bits I've read seem to me would be totally accessible at grades 6-8. Or better yet for the same age group, I'd recommend Builders of the Old World, the text I used in Calvert back in 6th grade -- a world history to 1500 and quite good from a Catholic perspective without the excesses of CKLH. For high schoolers, I'd recommend a good set of college textbooks. Spielvogel's Western Civilization is a good for a complete history from start to finish. But like most recent single volume world history textbooks, it devotes far too much time to the period post 1700. My recommended solution would be to use an ancient text (Chester Starr's A History of the Ancient World is very good) a medieval history text (none better than Warren Hollister's Medieval Europe: A Short History -- but get the 8th edition or earlier, more recent editions include a co-author who added a bunch of stuff on women's history and similar special interest topics) and then use the single volume history such as Spielvogel to fill in the rest.
While thinking about the question of how to deal with the Incarnation in the context of a history book, I went back and read Starr's chapter on the rise of Christianity. Starr does a number of things that I think are just right. He sets the stage with a discussion of Judaism in the first century BC both in Palestine and in the Hellenic world. He also contrasts the mystery cults with both Judaism and Christianity, mentioning their similarities, but also their important differences. However, although he tries very hard to be fair when dealing with the life of Christ, he runs into what I think are inherent difficulties when trying to bring a historian's tools to bear on the topic. On the one hand, he does not fall into denying that the miracles of Christ or the resurrection happened; on the other hand he hesitates to state them as fact since such things seem outside the historian's realm. And yet, as he points out, one of the things that distinguished Christianity from the surrounding pagan cults that focused on sacrificial meals and/or resurrection was that Christianity is founded upon a known historic revelation event, not some half-imagined happening in the mists of time. So he simply says he can't touch on the question of the miraculous, and tries to cover what he considers more historical in nature.
The result is unsatisfying, but I wonder if it is inevitable, since there is nothing a historian can add to the gospel accounts of Christ other than provide secular context for the surrounding events and conditions. No degree of historical analysis will allow us to know more certainly what Christ taught, or whether he was indeed the Son of God, or whether he rose from the dead. At best, a historian might be able to research the lineage of the documents that provide us with answers to these questions, but they could not tell us if the documents speak the truth.
In books written for children who are still at the storytelling stage, none of this really matters. As Christians, we should write books for this age (say, under 10 or 11) to reflect what we believe to be the truth. However, a textbook for older children is meant not merely to be a narrative of things past, but to reflect the process of historical analysis. In history texts of this type, I think the best approach available is to state that which can be said from external analysis while leaving the question of faith up to the reader. Thus, one should cite the only sources we have, explain their origins (and thus their point of view) and then summarize those elements of them which are relevant to the reader.
Thus, a junior high or high school text might say:
Jesus himself left no written documents or artifacts, so all that is known of him comes from accounts written by his followers in the first and second centuries AD, some of which are collected in the New Testament, and others of which were not included in the canon of scripture when it was determined by the 2nd and 3rd century Church. These documents take a number of forms. The Gospels are narrative accounts of the life, works and words of Jesus. Acts is a narrative about the early period of the Christian Church. The epistles were letters of instruction written by varius early authorities in the Church. Revelation is an extended account of a prophetic dream.And so on. It seems to be of historical importance to convey what Christians believe about the life of Christ, and yet ineffective to provide any kind of further historical analysis beyond a description of how these stories came to us through the books of the New Testament. And by taking the "according to these Gospel accounts" approach, the book no more endorses Christianity than it endorses Islam when it says, "According to Islam teaching, the Koran was reveal to Mohammad by the angel Gabriel..."
The Gospels describe Jesus as having been born of a virgin, who was told by an angel that she would...