https://www.penguin.co.uk/books/35329/the-upanishads-by-translated-and-edited-with-an-introduction-by-valerie-j-roebuck/9780140447491
An 'Upanisad' is a teaching session with a guru, and these thirteen texts, the 'Principal Upanisads', form a series of philosophical discourses between teacher...
the upanishads