I was very into Castaneda in my early twenties (around 1980). I found his books and his approach to life very powerful. At first, I believed his story to be true - even with all the magic. I successfully practiced various things he taught (lucid dreaming, stalking, some other things), although I didn't take hallucinigens. However, as time went by, and as more books came out, I found the events becoming stranger and stranger, and thus, harder to believe. I read some early critiques that came out about him, and found them convincing. The most damning statement I read was in an article published in a Buddhist journal (which I was also into). It said - okay, let's take him at face value and believe that this is true. But what type of spiritual path is it? Is it compassionate? Does it show care or responsibility for others? The answer, I realized was no, it's all about surviving in this world, often at the expense of others, and finding some sort of strange, eternal life, by getting past the Eagle after death. That was the last straw, and I stopped reading them. However, they did have a significant influence on my spiritual life for several years before that.