Nepal, Nov. 12 -- The prologue to Nigel Robert's memoir-like book begins with lines that will resonate with many of his generation:

'For a long time ... I put my work first; that was where I looked for purpose, identity and affirmation. Now, though, having lost whatever influence I once had, I find myself relatively indifferent to what I did or did not achieve, or how I am remembered by my colleagues. Those accounts feel settled.'

Those words set the tone for The Leopard and the Moon: A Journey in Dolpo, Nepal in which Roberts makes a cathartic journey retracing the footsteps of Peter Matthiessen and George Schaller half a century ago.

Matthiessen wrote the classic The Snow Leopard, which is mostly about working out his own demons and...