I have read a number of books in the “A Very Short Introduction” and I always enjoy them. While there are limitations of how much you can get across in such a small format, they are great resources. Mormonism: A Very Short Introduction by Richard Lyman Bushman is no exception.
Bushman is writing from a Mormon perspective, but this is what I liked about it. I actually found it to be a nice balance between Christian critiques of Mormonism and LDS-sponsored defences of Mormonism. While Bushman does attempt to portray Joseph Smith, Jr. and Mormonism is a positive light, he also doesn’t avoid the difficulties. Where there are problems, he identifies those problems.
I think that Mormonism: A Very Short Introduction could be helpful in having conversations with Mormons. It can’t be accused of being “anti-Mormon” and yet it is a bit more honest about the background and beliefs of Mormons than some of the official LDS publications.
If you are interested in learning more about Mormonism, I would encourage you to include Mormonism: A Very Short Introduction as a part of your research.