The best popular book on quantum theory is Nick Herbert's Quantum Reality, still selling briskly after twenty years in print. Nick was planning an update to QR when Louisa Gilder's The Age of Entanglement wonderfully filled that gap. A good companion to QR and AOE is Heinz Pagels's Cosmic Code. A few years ago mind-matter philosopher David Chalmers put out the call for a good first book on quantum theory for beginners (QR was rightly considered too advanced). I voted for the winner The Ghost in The Atom -- a series of BBC radio interviews with top quantum physicists with a superb introduction to quantum theory by PCW Davies. If you're curious about quantum mechanics one of these four books should be in your backpack.
So much has been written about tantra which is best learned without words. But while you're waiting to feel the touch of your tantric teacher you can usefully pass the time with Sexual Energy Ecstasy by the Ramsdales or Sexual Secrets by Nik Douglas and Penny Slinger. SEE is refreshingly simple and direct without oriental encumbrances, while SS is an veritable Whole Earth Catalog of tantra illustrated with beautiful line drawings by Penny.
The Great Book of Tantra by Indra Sinha
Nature, Man and Woman by Alan Watts
NEW RELATIONSHIPS WITH NATURE
Spell of the Sensuous by David Abrams
The Sacred Depths of Nature by Ursula Goodenough
The Joyous Cosmology by Alan Watts
Woman and Nature by Susan Griffin
Cosmicomics by Italo Calvino
Pihkal and Tihkal by Sasha and Ann Shulgin
The Pharmako Trilogy--P, G and D by Dale Pendell
Leaves of Grass by Walt Whitman
Not Man Apart by Robinson Jeffers
Cosmic Canticle by Ernesto Cardenal