Why has PB not mentioned much about V. Subramaniya Iyer in his notebooks?
did not mention Iyer in his notebooks because by the time PB started writing the notebooks, He (PB) was no longer the person that had studied in India or traveled the world. Secondly PB studied with many masters and teachers - including Zen, Tibetan, Chinese, Aztec, Egyptian, Moroccan, European, Thai, & Burmese throughout the middle of his life. These studies usually consisted of living in or near the master for a few years in their native country. I have always found it indicative of the shadow side of Hinduism that only the Hindu teachers have claimed PB as their chela alone; the others primarily retain a private and personal relationship with PB. Their names, by the way, are mostly to be found in the unpublished volumes "Talks in the Orient" (They are unpublished because the copyright problems are labor intensive.)