Since many higher-critical texts are written from a very sub-Christian point of view, it would be hard for me to imagine any good conservative positively introducing the issue. Duane Garrett has a pretty thorough critique of the liberal methods
Amazon.com: Rethinking Genesis: Garrett, Duane: Books
Gleeson Archer has probably the most damning criticism
Amazon.com: A Survey of Old Testament Introduction: Gleason Archer,Dillon Burroughs: Books
But if you want to be fair and read the best succinct opening to higher criticism, see the introductory notes to The Oxford Study Bible (either NRSV or RSV).
Lower Criticism, textual, the best opening would be Bruce Metzger's books.
But many liberals today are abandoning the higher-criticism project as outdated and resting on Enlightenment presuppositions. This is actually where postmodernism helps us. Who cares about the possible form or editorial processes which we by definition cannot have certain knowledge of its transmission? The text itself is where the real action is. That is liberals talking, not just conservatives.