Reddit mentions of The Triumph of the Moon: A History of Modern Pagan Witchcraft

For reliable sources:

High Magic's Aid by Gerald Gardner

Aradia: Gospel of the Witches by Charles Godfrey Leland

1: Witchfather: A Life of Gerald Gardner: Into the Witch Cult by Philip Heselton

Lid off the Cauldron by Patrica Crowther

The Triumph of the Moon by Ronald Hutton

Foundations of Practical Magic: An Introduction to Qabalistic, Magical and Meditative Techniques by Israel Regardie

A Witches' Bible by Janet and Stewart Farrar

Witchcraft for Tomorrow by Doreen Valiente

Modern Magick: Eleven Lessons in the High Magickal Arts by Donald Michael Kraig

Magical Power For Beginners: How to Raise & Send Energy for Spells That Work by Deborah Lipp

Fifty Years Of Wicca by Frederic Lamond

For essential materials,

-An athame

-A wand

-A pentacle

-A chalice

-Incense and censer

> Would I be considered a true Wiccan if I hid it from those around me?

Yes, you would be considered a "true Wiccan." Most Wiccans since the inception of Wicca kept secret the fact they were witches. It's only in very recent times that people are so forward about the fact that they're witches. I myself keep it pretty well hidden. Only those in my coven and my closest loved ones know that I'm Wiccan.

>When choosing a patron/matron do you pick from literally any gods/goddesses?

The concept of a patron/matron deity is relatively new to Wicca. Originally, the Goddess worshiped by the Witches was the Lunar Goddess of Fertility - often called Diana, Aradia, Hekate, Isis, the Queen of Elphame, etc. The original God worshiped by the Witches was the Horned God of Death and Resurrection - often called Pan, Cernunnos, Janicot, etc. However, in recent times, Wiccans (myself included) have begun working with all types of Pagan deities. So in short, yes, you can pick any god or goddess you feel a connection with.

> Can you celebrate the Wiccan holidays and still celebrate things like Christmas?

Yes, most Wiccans still celebrate cultural holidays such as Christmas.