I found this on the subject of what C.S. Lewis believed about the Bible:
"Attracted by Lewis’s clear presentation of Christianity, readers often are surprised when they discover Lewis’s assessment of the Bible. He discussed questions such as: What does it mean for Scripture to be “inspired by God†(2 Tim. 3:16)? Is it true and trustworthy? At first glance, readers may assume that Lewis had a high view of Scripture. He had said that the Gospels were not myths.5 He had been critical of those who reject supernatural elements of Scripture and had observed that modern theologians often base their conclusions on naturalistic assumptions instead of the biblical text.6 Further reading, however, calls his own view into question:
I have been suspected of being what is called a Fundamentalist. That is because I never regard any narrative as unhistorical simply on the ground that it includes the miraculous. Some people find the miraculous so hard to believe that they cannot imagine any reason for my acceptance of it other than a prior belief that every sentence of the Old Testament has historical or scientific truth. But this I do not hold, any more than St. Jerome did when he said that Moses described Creation “after the manner of a popular poet†(as we should say, mythically) or than Calvin did when he doubted whether the story of Job were history or fiction.7
Lewis believed that “all Holy Scripture is in some sense  though not all parts of it in the same sense  the word of God.â€Â8 The book of Job, for instance, lacking historical details and context, appeared to Lewis to be unhistorical. The idea that the creation account in Genesis was derived from earlier mythical and pagan accounts did not trouble Lewis. These earlier stories were retold and modified (whether consciously or unconsciously) until they became an account of “true Creation and of a transcendent Creator.†When this happens in Genesis, Lewis concluded, there is no reason to “believe that some of the re-tellers, or some one of them, has not been guided by God.â€Â9 In Lewis’s thought, Genesis conveys divine truth but not necessarily scientific or historical truth; still, God reaches us through its message.
In this same way, all Scripture, written in many literary styles, and for different purposes, may all be “taken into the service of God’s word.â€Â10 Whether it was produced by poets, by the Jewish community, by early Christians, whether modified by redactors (revisors) and editors, Lewis concluded, “On all of these I suppose a Divine pressure; of which not by any means all need have been conscious.â€Â11
In a personal letter, Lewis raised other issues that he thought were difficulties in the doctrine of inspiration, including inconsistencies in the genealogies in Matthew and Luke, inconsistencies in the account of the death of Judas, the admitted unhistorical nature of parables (which he believed may extend also to the stories of Job and Jonah), and Luke’s admission that he conducted research on his Gospel.12 Lewis concluded that because of this:
The total result is not “the Word of God†in the sense that every passage, in itself, gives impeccable science or history. It carries the Word of God and we (under grace, with attention to tradition and to interpreters wiser than ourselves and with the use of such intelligence and learning as we may have) receive that word from it not by using it as an encyclopedia or an encyclical but by steeping ourselves in its tone and temper and so learning its overall message.13
Similarly, he wrote, “That the over-all operation of Scripture is to convey God’s Word to the reader (he also needs inspiration) who reads in the right spirit, I fully believe. That it also gives true answers to all the questions (often religiously irrelevant) which he might ask, I don’t. The very kind of truth we are often demanding was, in my opinion, not even envisaged by the ancients.â€Â14 Indeed, Lewis considered this challenge of Scripture to be an asset: understanding God’s Word requires not only the intellect but also the entire person.
Lewis clearly believed Scripture has authority and communicates God’s word, but his grounding of that authority is confusing to many. On this point, Lewis, who was ordinarily objective in his theological understanding, added a layer of subjectivity. If Scripture only in some sense is the word of God, then in some sense it is not. Parts of it are trustworthy; others must be less so. The problem such a view creates is, how is the Christian to decide which part to trust? If all Scripture can be the word of God but not communicate truth, then inspiration is of little practical consequence.
Lewis’s statements may frustrate Christians who hold that Scripture is inerrant. One wishes that Lewis had taken more time to examine other apologetic responses to his objections against inerrancy, but the message of his writings remains clear. Lewis did not believe in an inerrant Bible, though he did believe that Scripture was in some sense inspired. Some have tried to harmonize Lewis’s words with biblical inerrancy and infallibility; unfortunately, this attempt is futile."
http://www.equip.org/free/JAL400.htm