While that book may have gotten everyone's attention, it was his second book that really cemented his place as a New Thought author.
"The Magic of Believing" took the principals of the first book and expanded on them.
And it also told in depth how he came to believe these things himself.
He is part one of the book at YouTube.
I have to warn you though, this is a VERY abridged version.
You cannot take the original book and read along.
To get everything you need to read the book, but this will give you some idea of how Bristol thought.