First books about Wicca (its not really called Wiccanism, but I can see why you thought it might, since Wiccan and Pagan end the same way, you would think that you would do that, but actually Wicca is the word you would use in that sentence, but not Paga- 😉 )
As for learning about Wicca, I suggest reading these books, this is the advice I wish I had been given, instead of the standard advice others always give. The most famous Wiccan, Gerald Gardner, gave people his novel High Magick’s Aid when he wanted to find out if they would like Wicca. I suggest you go ahead and start in the same place. If you like that, I suggest getting his other non-fiction books about Witchcraft and picking up a few of the titles about Wicca by Sorita d’Este to be study aides for you while you are reading those and to help fill in details and history.
Here is a link to a partial index of some of my posts http://spiritscraft.tumblr.com/index. Its a work in progress, but I do suggest reading any of those that peak your interest. Much of my blog is not introductory—although I am happy to answer intro questions!
The story of how I got into witchcraft and paganism is kinda long. When I was a kid I was always interested in witches. My family was kinda new age and taught me a few basic spells and energy workings. And I first heard about Wicca in high school because of TV shows and movies. In University I learned about paganism through my Celtic Studies courses which interested me because of my heritage and I met some actual witches and went to some of their events, but decided I was going to be a liberal Christian. I went to church for a couple years, and I got very interested in Saints. After a few unpleasant incidents, I decided a spirituality with more diverse gods would suit me better and I sought out paganism and witchcraft again. From there I looked for a group and met my circle.
I either grow herbs from seeds I buy at local shops, online from a local nursery (Horizon Herbs—its near me), and I buy herbs from local stores or from Mountain Rose Herbs online (also near me). For unusual herbs, I get them from Alchemy Works or trade with other witches. I buy gems from local rock and gem stores. I also find a lot of the rocks I use out and about. I get a lot of my other supplies from craft stores around Halloween, and from sellers on Etsy.