This is a fine book for Latter-day Saints (i.e., Mormons) who might be struggling to figure out who many of the leading lights in Christian theology are and something about what they believed or did not believe.
The fifty "key" figures are listed alphabetically by their surname, but there is a useful "Chronological list of Contents" (pp. vii-viii). The entries are competently done. The choice of "key" figures is also acceptable, even if it is a bit odd to have an entry on Ludwig Feuerbach, who is described as an "anti-theologian," meaning that he was an atheist.
There are a few other similar oddities or anomalies, but this is common among those known as "theologians." Among the fifty entries are writers like Justin Martyr, Irenaeus, Tertullian, Origen, Augustine, Anselm, and Aquinas. They are part of the antique world. Then there are also entries on later writers such as John Calvin, Søren Kierkegaard, Karl Barth, and Paul Tillich.
Eight of the authors whose views are described were still alive when the book was published.