This is Osho's interpretation of the Bikram Tantra. Tantra seeks to go beyond the duality, such as good and evil, and transcend them, which is difficult to understand. He says that Tantra is the only sacred document to accept the body and sex as a springboard to enlightenment. However, Tantra does not often speak of sex.
Clocking in at 1300 pages, Book of Secrets is a long, but easy read with fairly big type. I got tired of reading about these 112 meditation techniques at times, but I forged on. There is DVD with Osho speaking, but I found it boring because he spoke so passively and slowly. Osho suggests picking out the technique which is right for you, which for me would be the one called "dissolving into darkness". These techniques are for enlightenment, which I do not think I'm ready for yet. Osho says that some meditators come to the edge where there ego is going to dissolve into the void, but then turn back for fear of losing it. One should be meditating all the time, which means that you should always do everything with awareness of what your doing whether eating, sleeping, walking, and working.
Regarding dreaming, Osho is not so much impressed with the meaning of dreams. He says that one should learn to control dreams until one learns to gain a yoga sleep without dreams, which is deeper and more refreshing. Dreaming to him is more mind chatter, just like the aimless thoughts that run through the mind, which one should be aware of, but not attached to.
He explores other questions of meditation such as how do you know you are truly enlightened? The mind can trick you into a false enlightenment. Is your search for enlightenment just another ego trip? You have had greed and lust for material things, do you now just want add enlightenment to your possessions? This attitude will not work. One must totally surrender the ego, preferably to a guru. The guru is not so important, but the surrender is. One can achieve enlightenment even with a charlatan guru if you are ready for it. By silencing the mind's thoughts and ridding one's self of desire, bliss is achieved, which is a state of not being in misery.
Love is achieved, but this is not the ordinary love that is mixed with hate that exists in relationships such as marriages. This love is impersonal, passionless, non-attached, and non-dual. He says that this is what Jesus meant by saying that God is love. Osho says that Jesus was a guru living among Jews who did not have any familiarity with Eastern thought of India.
Eastern religions were developed by people who had renounced riches, such as Buddha, because they were bored with the pleasures of this world. Once someone becomes rich and has everything, they suffer from lack of goals and meaning in their lives.
Osho is often critical of marriage, but says that he is not against it. He says that love is spontaneous in the beginning when it is given from an overflowing. Once someone seeks to secure love in a marriage, the love dies because love becomes just a duty. Partners resent each other for making each other into possessions, who actually should be treated as persons who have pure freedom.