I don't know of any that are totally unbiased. Everybody has a point of view, after all, or they probably wouldn't have written a book in the first place.
My best advice would be to read books from a VARIETY of points of view, and then ask yourself what sounds reasonable and plausible to you. After all, yours is ultimately the only point of view that matters in your decision.
I don't know of any, just check some out and pray about it. Thats what I did and I feel better. Just look at the church, it teaches you to be close to your family, your friends, and keep the laws of the land. I don't see anything wrong about that.
Any book on Mormonism which is accurate and unbiased will describe it as a cult. So the easiest way to choose a book about Mormonism which is accurate and unbiased is to pick up the most critical and negative book about Mormonism you can find.
I'm not sure if my answer is really all that valuable, but given the other answers here it might not be so bad.
In my opinion, to find an unbiased book that is accurate about Mormonism is somewhat of a paradox. If Somebody is passionate enough to find out what really happened, they probably either have an opinion, or acquire one in the process. Many people are strongly opposed to the church and many people are strong supporters of it. People writing books on the subject may easily fall into one of these categories.
Alternatively, you may find people who have no concern one way or the other. But in a situation like that, I wouldn't expect that your information would be quite as in-depth as a person who does care or does have an opinion.
Frankly, God doesn't require us to study out each and every variant of religion and of each doctrine for us to know the truth. The Holy Ghost testifies of truth to us. If you pray with sincere desire to know the truth. As you search the truth out, the Holy Ghost will guide you.
As far as finding the truth without the Holy Ghost, that's a matter of how you define truth. If you're talking about the facts of events and the facts of intents and purpose behind those events, I don't think there's ever been a perfectly kept record. As such any portion of information that may be "accurate" by itself, can most always be distorted by those who are missing other key information, or who may willfully be trying to skew the information to either show a more positive or negative light. In the end, what ultimately matters is the conclusion that you make through your own personal study and experience.
I can tell you the church is true, or I can tell you that it isn't. The fact is that me telling you, alone, could not service to actually convince you of anything either way. If it ever were to matter to you, it must be because it was something that you found out for yourself.
For example, I can talk to a hundred people today that will tell me that I have ultimately no hope of starting a successful business with volumes and volumes about why not. At the same time, I can talk to another hundred people who will tell me that I can in fact. These people would have volumes of supporting information as well. Beyond that there are plenty of people who would attempt to capitalize off of whichever I would believe from them. They may try to sell me an investment under the idea that I can't make it without them, or they may try and sell me "information" on how I can go about achieving things on my own. Many of these people have vested interest in what I actually decide, but none of them are actually capable of convincing me, beyond a shadow of a doubt, whether or not I can form a successful business. Only I can do that. Once I have established a successful business however, I will be able to see the truth from the lies. All of the people who told me that I couldn't were wrong. And some of the people that told me I could may have had some bad information as well. Ultimately, in this scenario, I did and so I know the truth for myself. Nobody would ever be able to convince me that it isn't possible at that point.
Going along with this analogy, in my search for information, I may encounter other people with successful businesses that they have already established. These people will tell me that it is, in fact, true that I can, no matter what anybody else says. They can do this with absolute surety because they have already pr oven it to themselves. But even their statements of absolute and demonstrated certainty cannot serve to prove to me whether, or not I can establish a successful business. Again, only I can determine that for myself. And when I have the answer, I won't need to worry about anybody Else's opinion relating to it.
Finding the true Gospel is a very similar endeavor. There will always be people there to tell you one way or another. Some of them will be convinced that they are right based on their own experiences and others may simply be trying to profit off of whatever you will believe. None of these people can serve to convince you of what is or is not true. You will have to decide for yourself.
What some of us can do that might help you as you seek information is provide you with our own personal experiences. You would have to take it for what it's worth though. But as far as finding an actual source of certifiably unbiased information on the subject, I have my doubts that any really exists.
Here are several good possibilities for unbiased resources:
1. "Mormon America" by Richard and Joan Ostling
Richard and Joan Ostling are esteemed reporters for "Time" magazine, and the Associated Press; and wrote this very well reviewed,very thorough and unbiased introduction to Mormonism.
2. DAniel Ludlow, "Encyclopedia of Mormonism" (by former head of BYU Religion Department)
3. Leonard J Arrington and Davis Bitton - "The Mormon Experience: A History of the Latter-day Saints" (Arrington is former Church Historian and has excellent credentials as a professional historian)
4. Jan Shipps, "Mormonism: The Story of a New Religious Tradition" (Shipps is a non-LDS, but very knowledgeable and understanding of LDS history and doctrine).
You can probably find all or most of these in a good library, or do an "Inter-Library loan for them --