Spiritualist Basics is a good starting point for understanding Spiritualism and mediumship. The book is an explanation of what Spiritualism is about, written for someone who is unaware that Spiritualism exists as a religion, science, and philosophy, but has heard of "psychic readings".
If you're not already logged in, log in and click on the book cover image to see the download page. New users will need to create a login. You'll need your email address, but no worries, as I wouldn't do anything unethical or spam-like with it and have the Law of Cause and Effect rain down on me.
Spiritualist Basics is a copyrighted document, but you are welcome to copy and distribute it if you comply with the restrictions listed in the Copyright. There is no charge for the book, but please be sure to make a donation to the First Spiritualist Temple church. First Spiritualist is where I officially began my learning in Spiritualism, and thereby enabled me to write this book for you. What goes around comes around, and your donation will complete the circle, in a positive way.