The tenets of Mormonism were supposedly revealed to the prophet Joseph Smith over a period of years. The Book of Mormon, though it has been recognized as the classic text (Smith having found the plates in the Hill Cumorrah in New York), was only the first of these revelations and is, for the most part, quite orthodox. (It is the supposed history in the book which in questionable, including a visit by Jesus Christ to the Americas.) The full revelation developed over the years, and the final doctrinal structure was expressed by Smith in a funeral talk given for King Follett (a disciple) shortly before Smith's own death at the hands of a mob.
Smith claimed that God was once a mortal man, and is now an exalted man. That all people who have ever lived were originally spirits with God, and our present incarnation in flesh is to enable us to become Gods ourselves. Such deification is offered to those who marry in a Mormon temple ceremony and have children, thus perpetuating the incarnational and deification processes. Such beliefs led to the practice of polygamy (now discontinued), and the current emphasis on family life. Early Mormons were looking for the coming of God's kingdom, and this was to be fulfilled by following the directions from Smith's revelations. This necessitated the setting up of a theocratic state, and resulted in repeated persecutions during Smith's lifetime until, after his death, "the Saints" (as they were called) were forced under the leadership of Brigham Young to settle in the (then) isolated area which has since become the State of Utah where the theocratic experiment could proceed. When Western expansion in the USA lead to Utah's absorption into the Union, and Federal law resulted in a crackdown on polygamy, the Mormons could no longer be geographically isolated. This, in turn, meant that they had to isolate themselves spiritually by strict observances imposed by the leadership - and in this way were similar to JWs. Yet, the Mormons relate to the larger culture in a way which JWs do not.
So . . . read the Book of Mormon. Though you'll find it quite boring, and it is intimidating when the missionaries tell you that, by praying over it, you'll be convinced of its divine inspiration - this is important because you'll see that the book in itself does not support the fully developed Mormon religion.
Mormon America: The Power and the Promise was written by Richard N. Ostling and Joan K. Ostling, and published by HarperCollins. Written by non-Mormons, the book covers Mormon history, theology and practice.
No Man Knows My History: The Life of Joseph Smith the Mormon Prophet by Fawn M. Brodie (originally in 1945 but still in print) is a classic by an ex-Mormon taking a critical view of Smith's life and career.
Mormonism: The Story of a New Religious Tradition by Jan Shipps - a woman who moved to Utah, took up an interest in Mormonism (but not converting), and became a religious scholar in her own right. Her thesis is that Mormonism is a new religion which springs from, but is distinct from Christianity - similar to Christianity's being distinct from Judaism. This is not an easy read, but may give additional insights.
There is plenty of information on the internet - and in fact Mormonism is considered by many to be the "other" great American cult (other than JWs) - and there is no reason why anyone should be lead step by step into a conversion if they are wary of this religion.