Introductions are books that introduce the books of the Bible. A typical introduction will cover ideas of authorship, canonization process, themes, date of composition, provenance (place and date of composition/origin), and discuss the intended audience. It is not a commentary on individual passages, but give details about the composition and reception of the biblical book.
Surveys are books that cover, in typically less detail, the same ideas of an Introduction as well as discuss the themes and message of the books of the Bible.
Introductions and Surveys vary in quality and/or theological bent. One of the major differences is the theological bias of the author. Critical, or liberal, authors will deny miracles and historical prophecy, as such, they will date books of prophecy as being after all the events described (ex eventu). Critical authors will cover many of the tricky issues of dating the book that some conservative, less critical authors will ignore. One easy litmus test for an Old Testament/Hebrew Bible author is to check their dating or authorship of Deuteronomy. If the author argues for Mosiac authorship of the entire book, it is a very conservative author. If the author argues for mostly Mosiac authorship, then the author is fairly conservative. If the author argues that it is a seventh century, or later, composition with no relationship to Moses (possibly denying a historical Moses) then the author is on the more critical/liberal side. For the New Testament the liberal authors will date the books of the New Testament to a slightly later period. Instead of dating the Gospels to the lifetime of the disciples, all the gospels will be dated after 70 CE (the date of the destruction of the Temple), or much later to fit some other ideal for the author.