What Jesus taught in secret is the story of the unexpected discovery that the Huna code had been used in the writing of the Four Gospels to conceal the secret teachings of Jesus.
I read this a long time ago and though I don't believe that the man commonly called Jesus was in any way attempting to start a new religion I find many things about that period in time and theories and ideas about him to be fascinating.
AFAIK this book was only printed on a very small run. I happened to find it at a used bookstore in Chapel Hill where I found lots of interesting small print goodies over the years including at one time a great deal of private printings from the Masonic Lodge. I didn't buy those but I spent hours looking through them while they were there.
This book goes into detail about a secret doctrine that Jesus taught that the Gnostics have passed on for the last two millennia. It is up to the reader to decide how likely that scenario is.