Recent editions of the Book of Mormon (and by recent I mean way after Joseph Smith died...although according to Wikipedia, it means since 1920) have included summaries before each chapter. These are helpful little blurbs that can make it easier for the reader to keep track of the important plot developments and doctrinal teachings in each chapter.
For example, here is the chapter summary from 1 Nephi Chapter 19, which is twenty-five verses long:
Before reading that chapter in detail, you already know that Nephi's going to create and describe his records, a rough timeline for when the events of Nephi's life take place will be established, Nephi will speak of Christ's atonement, and then he'll go off on a speech about God's master plan for the Jews and the whole scattering/gathering business.Nephi makes plates of ore and records the history of his people—The God of Israel will come six hundred years from the time Lehi left Jerusalem—Nephi tells of His sufferings and crucifixion—The Jews will be despised and scattered until the latter days, when they will return unto the Lord.
But if you look at the summary for our current chapter, 2 Nephi 17, which is also twenty-five verses long, you'll read:
Ephraim and Syria wage war against Judah—Christ will be born of a virgin.Before reading this chapter in detail, you already know...that Nephi will quote Isaiah's description of Biblical history and impart the not-so-shocking-revelation that Jesus' mother will be a virgin.
What do these twenty-five verses accomplish that wasn't already done in the Bible? Nothing.