I excluded fiction from this list. I also excluded many scientific and technical books which are truly my favorites but they would not be appropriate here. Another excluded category is the esoteric books.
The following are the books that I go back, revisit and enjoy each time.
The Road to Reality: A Complete Guide to the Laws of the Universe
Roger Penrose
Vintage (2007), ISBN: 978-0679776314
On Space and Time
Shahn Majid
Cambridge University Press (2008), ISBN: 978-0521889261
Warped Passages
Lisa Randall
Harper Perennial (2006), ISBN: 978-0060531096
Einstein: His Life and Universe
Walter Isaacson
Simon & Schuster (2008), ISBN: 978-0743264747
The Veil of Isis
Pierre Hadot
Belknap Press of Harvard University Press (2008), ISBN: 978-0674030497
Wholeness and the Implicate Order
David Bohm
Routledge, Reissue edition (2002), ISBN: 978-0415289795
The Mind of God
Paul Davies
Simon & Schuster (1993), ISBN: 978-0671797188
In Search of Memory
Eric R. Kandel
W. W. Norton & Company (2007), ISBN-13: 978-0393329377
The Dreaming Universe
Fred Alan Wolf
Touchstone (1995), ISBN: 978-0684801599
The Cosmic Landscape
Leonard Susskind
Back Bay Books (2006), ISBN-13: 978-0316013338
The Conscious Mind
David Chalmers
Oxford University Press, USA (1997), ISBN-13: 978-0195117899
The Spiritual Teachings of Ramana Maharshi
Shambala Publications (2004), ISBN: 978-1-59030-139-5
The Art of Being and Becoming
Hazrat Inayat Khan
Omega Publications (2005), ISBN: 978-0930872410
The Music of Life
Hazrat Inayat Khan
Omega Publications (1998), ISBN: 978-0930872380
The Way: Using the Wisdom of Kabbalah for Spiritual Transformation and Fulfillment
Michael Berg
Wiley (2002), ISBN: 978-0471228790
The Power of Now: A Guide to Spiritual Enlightenment
Eckhart Tolle
New World Library (2004), ISBN: 978-1577314806
Consciousness Is All: Now Life Is Completely New
Peter Francis Dziuban
Blue Dolphin Publishing, Inc (2006), ISBN: 978-1577332022
The Himalayan Masters: A Living Tradition
Pandit Rajmani Tigunait
Himalayan Institute Press (2002), ISBN: 978-0893892272
Essentials of Mahamudra
Khenchen Thrangu Rinponche
Wisdom Publications (2004), ISBN: 978-0861713714
The Awakening of Intelligence
J. Krishnamurti
Harper Collins (1987), ISBN: 0-06-064834-1
The New Path: My Life with Paramhansa Yogananda
Swami Kriyananda
Crystal Clarity Publishers (2009) , ISBN: 978-1565892422
Awaken to Superconsciousness
Swami Kriyananda
Crystal Clarity Publishers (2008), ISBN: 978-1565892286
I: Reality and Subjectivity
David R. Hawkins
Veritas Publishing (2003), ISBN: 978-0971500716
The Hermetica: The Lost Wisdom of the Pharaohs
Timothy Freke and Peter Gandy
Tarcher Penguin (2008), ISBN: 978-1585426928
The Four Faces of the Universe
Robert Kleinman
Lotus Press (2007), ISBN-13: 978-0940985919
Quiet Mind, Fearless Heart
Brian Luke Seaward
Wiley (2004), ISBN-13: 978-0471679998
The Sufi Path of Love
William C. Chittick
State University of New York Press (1983), ISBN-13: 978-0873957243
Me & Rumi: The Autobiography of Shams-i Tabrizi
William C. Chittick
Fons Vitae (2004), ISBN: 978-1887752527
The Illustrated Rumi
Coleman Barks and Michael Green
Broadway Books (1997), ISBN: 978-0767900027
Open Secret: Postmessianic Messianism and the Mystical Revision of Menahem Mendel Schneers
Elliot R. Wolfson
Columbia University Press (2009), ISBN: 978-0231146302
I Won’t Let You Go: Selected Poems
Rabindranath Tagore
Bloodaxe Books (1991), ISBN: 1852241195
Collected Poems: 1953-1993
John Updike
Knopf (1993), ISBN: 0-679-42221-8
The Courtier and the Heretic: Leibniz, Spinoza, and the Fate of God
Matthew Stewart
W. W. Norton & Company (2007), ISBN: 978-0393329179
The Soul of Rumi
Coleman Barks
Harper (2002), ISBN: 0-06-060453-0
The Egyptian Book of the Dead (The Book of Going Forth by Day)
Eva Von Dassow, eds.
Chronicle Books (1994), ISBN: 1098765
Kundalini Rising: Exploring the Energy of Awakening
G.K. Khalsa, A.Newberg, S.Rhada, K.Wilber, J.Selby
Sounds True, Incorporated (2009), ISBN: 978-1591797289
Kundalini : The Energy of the Depths : A Comprehensive Study Based on the Scriptures of Nondualistic Kasmir Saivism (Suny Series in the Shaiva Traditions of Kashmir)
Lilian Silburn
State University of New York Press (1988), ISBN: 978-0887068010
Exploring Chakras: Awaken Your Untapped Energy
Susan G. Shumsky
New Page Books; 1 edition (May 2003) , ISBN: 978-1564146564
The Secret Teachings of the Tao Te Ching
Mantak Chia and Tao Huang
Destiny Books (2005), ISBN: 978-0892811915
The Mind Beyond Death
Dzogchen Ponlop
Snow Lion Publications (August 29, 2008) , ISBN: 978-1559393010
Sleeping, Dreaming , and Dying
The Dalai Lama
Wisdom Publications (2002), ISBN: 978-0861711239
The Journey of Man
Spencer Wells
Random House Trade Paperbacks (2004), ISBN: 978-0812971460
Alexander: The Ambiguity of Greatness
Guy MacLean Rogers
Random House Trade Paperbacks (2005), ISBN: 978-0812972719
Salonica: City of Ghosts
Mark Mazower
Vintage (2006), ISBN: 978-0375727382
Osman’s Dream
Caroline Finkel
Basic Books (2007), ISBN: 978-0465023974
Paul: The Mind of the Apostle
A.N. Wilson
W. W. Norton & Company (1998), ISBN-13: 978-0393317602
Handbook of Semiotics
Winfried Noth
Indiana University Press (1995), ISBN: 978-0253209597
Kant and the Platypus
Umberto Eco
Mariner Books (2000), ISBN: 978-0156011594
The Turkic Speaking Peoples
Ergun Cagatay and Dogan Kuban eds.
Prestel (2008), ISBN: 978-3791335155
Empires of the Word: A Language History of the World
Nicholas Ostler
Harper Perennial (2006), ISBN: 978-0060935726
Course in General Linguistics
Ferdinand de Saussure
McGraw-Hill Paperbacks (1966), ISBN: 07-016524-6
The Language Instinct
Steven Pinker
Harper Perennial Modern Classics (2007), ISBN: 978-0061336461
The World’s Major Languages
Bernard Comrie
Routledge (2009), ISBN: 978-0415353397
Origin of Language
Merritt Ruhlen
Wiley (1996) , ISBN: 978-0471159636
Genes, Peoples, and Languages
Luigi Luca Cavalli-Sforza
University of California Press (2001), ISBN: 978-0520228733
Mapping Human History: Genes, Race, and Our Common Origins
Steve Olson
Mariner Books (2003), ISBN: 978-0618352104
Before the Dawn: Recovering the Lost History of Our Ancestors
Nicholas Wade
Penguin (2007), ISBN: 978-0143038320
Egyptian Language
E.A.W. Budge
Barnes & Noble, ISBN: 0-7607-1578-5
Pyramid Quest
Robert M. Schoch
Tarcher (2005), ISBN: 978-1585424054
Egyptian Cosmology
Moustafa Gadalla
Tehuti Research Foundation (2001), ISBN: 978-0965250931
An Illustrated Encyclopedia of Traditional Symbols
J.C. Cooper
Thames & Hudson (1987), ISBN-13: 978-0500271254
I wanted to list my favorite Anandamurti books separately
Idea and Ideology
ASIN: B0006E8NAE
Namami Krsna Sundaram
ISBN: 978-8172521110
Namah Shivaya Shantaya
ISBN: 81-7252-098-0
Discourses on Tantra. vol. 1
ISBN: 81-7252-107-3
Discourses on Tantra. vol. 2
ISBN: 81-7252-022-0
Varna Vijinana: The Science of Letters
ISBN: 81-7252-179-0
The Spiritual Philosophy of Shrii Shrii Anandamurti: A Commentary on Ananda Sutram
Avadhutika Ananda Mitra Acarya
ISBN: 81-7252-119-7
all available from Ananda Marga Publications
