| title | ISBN-13 (ISBN-10) | year of publica- tion | other author(s) |
|---|---|---|---|
| Green Psychology: Transforming our Relationship to the Earth | 978-0-89281-798-6 (0-89281-798-4) | 1999 | Ralph, Ph.D. Metzner |
| Sacred Vine of Spirits: Ayahuasca | 978-1-59477-053-1 (1-59477-053-0) | 2005 | |
M.D · M P · Ph.D. · R.D. · R. P. · R.Ph. · Ralph Metzner