Since Kabbalah is one of my fields of interest, let me recommend some beginning/intro works on that subject first:
By Gershom Scholem:
Major Trends In Jewish Mysticism
On The Kabbalah And Its Symbolism
Kabbalah
On The Mystical Shape Of The Godhead: Basic Concepts In Kabbalah
Zohar: Readings From The Book Of Splendor
By Lawrence Kushner:
Honey From The Rock
God Was In This Place And I, I Did Not Know
The Book Of Letters: A Mystical Hebrew Alphabet
The River Of Light: Jewish Mystical Awareness
The Way Into: Jewish Mystical Tradition
Sparks Beneath The Surface: A Spiritual Commentary On The Torah
The Thirteen Petalled Rose, by Adin Steinsaltz
Jewish Mystical Testimonies, by Louis Jacobs
The Essential Kabbalah: The Heart of Jewish Mysticism, by Daniel C. Matt
Meditation and Kabbalah, by Aryeh Kaplan
The Origins of Jewish Mysticism, by Peter Schafer
Keter: The Crown Of God In Early Jewish Mysticism, by Arthur Green
The Sabbath Soul: Mystical Reflections On Holy Time, by Eitan Fishbane
Jewish Mysticism And The Spiritual Life: Classical Texts, Contemporary Reflections, by Lawrence Fine, Eitan Fishbane, and Or N. Rose
And of course, Aryeh Kaplan's translations of Sefer Yetzirah and Sefer ha-Bahir, along with Daniel Matt's multi-volume translation of the Zohar.
On Tanach and other sacred text:
The Jewish Study Bible, by Adele Berlin, Marc Zvi Brettler, Michael Fishbane
The Five Books of Moses, by Everett Fox (not only the best translation so far of the Torah, but excellent footnotes)
The Five Books of Moses, by Robert Alter (the next best translation, with excellent commentary)
Rashi's Torah Commentary: Religious, Philosophical, Ethical, and Educational Insights, by Pinchas Doron
Ramban: Commentary on the Torah, by Charles Chavel (tr.)
Sforno: Commentary on the Torah, by Raphael Pelcovitz (tr.)
The Language of Truth: The Torah Commentary of the Sefat Emet, by Arthur Green
Back to the Sources: Reading the Classic Jewish Texts, by Barry Holtz
Finding Our Way: Jewish Texts and the Lives We Lead Today, by Barry Holtz
How to Read the Bible: A Guide to Scripture, Then and Now, by James Kugel
The Midrashic Imagination: Jewish Exegesis, Thought, and History, by Michael Fishbane
On Jewish History:
A History of the Jewish People, by H.H. Ben-Sasson
A History of the Jews in the Modern World, by Howard Sachar
The Jew In The Modern World: A Documentary History, Paul Mendes-Flohr (ed.)
Zakhor: Jewish History and Jewish Memory, by Yosef Hayim Yerushalmi
On Jewish theology and philosophy:
Contemporary Jewish Theology
Contemporary Jewish Ethics and Morality, both edited by Elliot Dorff and Louis Newman
Choices In Modern Jewish Thought, by Eugene Borowitz
The Jewish Philosophical Reader, edited by Dan Frank, Oliver Leaman, and Charles Manekin
Not In Heaven: The Nature and Function of Jewish Law, God Man and History, and Essential Essays on Judaism, by Eliezer Berkovits;
Halachic Man
The Lonely Man of Faith, both by Joseph Soloveitchik;
A Heart of Many Rooms: Celebrating the Many Voices Within Judaism
A Living Covenant: The Innovative Spirit in Traditional Judaism, both by David Hartman;
Horeb: A Philosophy of Jewish Laws and Observances, by Shimshon Refael Hirsch
A Tree of Life: Diversity, Flexibility, and Creativity in Jewish Law, by Louis Jacobs
A Living Tree: The Roots and Growth of Jewish Law, by Elliot Dorff and Arthur Rosett
The Unfolding Tradition: Jewish Law After Sinai, by Elliot Dorff
For The Love of God and People: A Philosophy of Jewish Law, by Elliot Dorff
The Exegetical Imagination: On Jewish Thought And Theology, by Michael Fishbane
Heschel gets his own category:
God In Search Of Man
Man Is Not Alone
Heavenly Torah As Refracted Through The Generations
Man's Quest For God
The Sabbath
Moral Grandeur and Spiritual Audacity
Commentary and Chassidut
The Language of Truth: The Torah Commentary of the Sfat Emet
Upright Practices, The Light of the Eyes: The Commentaries of Rabbi Menahem Nahum of Chernobyl, both translated and elucidated by Arthur Green
Your Word Is Fire: The Hasidic Masters On Contemplative Prayer, Arthur Green and Barry Holtz, eds.
The Seven Beggars & Other Kabbalistic Tales of Rebbe Nachman of Breslov
The Lost Princess & Other Kabbalistic Tales of Rebbe Nachman of Breslov, both translated and elucidated by Aryeh Kaplan
A Heart Afire: Stories and Teachings of the Early Hasidic Masters
Wrapped In A Holy Flame: Teachings and Tales of the Hasidic Masters, both by Zalman Schachter-Shalomi
God In All Moments: Mystical and Practical Spiritual Wisdom from Hasidic Masters, Or N. Rose and Ebn Leder, eds.
Four Chassidic Masters, R. Abraham Twerski
Living Waters: From the Commentary of the Mei ha-Shiloach, Betsalel Edwards (tr.)
Mipninei Noam Elimelech, by R. Tal Moshe Zwecker
Kedushat Levi, Eliyahu Munk (tr.)
The Holy Fire: The Teachings of Rabbi Kalonymus Kalman Shapira, the Rebbe of the Warsaw Ghetto, by Nechemiah Polen
Sacred Fire: Torah from the Years of Fury (1939-1942), by J. Hershy Worch
Opening the Tanya
Learning from the Tanya
Understanding the Tanya, all by Adin Steinsaltz
Prayer and Holidays:
Jewish Holidays, by Michael Strassfeld
Days of Awe, by S.Y. Agnon
The Celebrating the Jewish Year series, by Paul Steinberg
Repentance: The Meaning and Practice of Teshuvah, by Louis E. Newman and Karyn D. Kedar
A Guide To Jewish Prayer, by Adin Steinsaltz
Davening: A Guide to Meaningful Jewish Prayer, by Zalman Schachter-Shalomi
Entering Jewish Prayer
Entering the High Holidays, both by Reuven Hammer
To Pray As A Jew, by Hayim Halevi Donin
The Way Into Jewish Prayer, by Lawrence Hoffman
The Jewish Way: Living the Holidays, by Irving (Yitz) Greenberg
This Is Real and You Are Completely Unprepared: The Days of Awe as a Journey of Transformation, by Alan Lew