This is an excerpt from “Everything in Its Place,” a posthumous collection of writings by Dr. Sacks.

As a writer, I find gardens essential to the creative process; as a physician, I take my patients to gardens whenever possible. All of us have had the experience of wandering through a lush garden or a timeless desert, walking by a river or an ocean, or climbing a mountain and finding ourselves simultaneously calmed and reinvigorated, engaged in mind, refreshed in body and spirit. The importance of these physiological states on individual and community health is fundamental and wide-ranging. In 40 years of medical practice, I have found only two types of non-pharmaceutical “therapy” to be vitally important for patients with chronic neurological diseases: music and gardens.

The wonder of gardens was introduced to me very early, before the war, when my mother or Auntie Len would take me to the great botanical garden at Kew. We had common ferns in our garden, but not the gold and silver ferns, the water ferns, the filmy ferns, the tree ferns I first saw at Kew. It was at Kew that I saw the gigantic leaf of the great Amazon water lily, Victoria regia, and like many children of my era, I was sat upon one of these giant lily pads as a baby.

As a student at Oxford, I discovered with delight a very different garden — the Oxford Botanic Garden, one of the first walled gardens established in Europe. It pleased me to think that Boyle, Hooke, Willis and other Oxford figures might have walked and meditated there in the 17th century.