You do not 'summon' 'the' book of shadows. A BoS is in terms a journal/book where you write down spells/rituals, spiritual experiences, thoughts, some dreams, notations, etc. There are some pre-written which you can find but most people will make their own as time progresses.
As has already been mentioned, you do not summon a Book of Shadows.
A Book of Shadows can be thought of as a sort of magical journal where you write down spells, rituals, herb lore, correspondences, magical lore, dreams, trance visualizations, your thoughts about your Craft, and anything else you feel the need to keep on hand. For most of us this is something that we create in our lifetime. A few have been lucky enough to have been given one by an older Witch or practitioner.
There is an excellent article about what a Book of Shadows is and about some of the mythology about its origins that you might like to read. You can find it at http://wicca.cnbeyer.com/grimoire.shtml
as Lark said, you make it yourself. any and all facts and experiences involving your path should be written down. it's a reference aid and perhaps one day can be passed down to your children. it can be made from any notebook, some people even choose to make the notebook them self. i have several books, one has lined paper, and one is hand made paper, the rest are notebooks without lines. personally i like those the best because i can sketch things and not worry about lines showing through.
you can also have feather, leaves, flowers and dried herbs placed between the pages, glue beads or colour the pages if you wish. the whole thing should be personalized. when done, you can put a magic seal on it if you want, or bless it. there is really no one way to make a BoS, if it feels right to you and it will help you with your magic/studies, then add it.
Lark, im one of the few lucky one, mine was handed down to me by my ancestors a faily of witches.
To Kroni101, a Book of Shadows can be a school notebook, a fancy leather book, just think of it like a diary but here you write your spells and so forth, just like Lark wrote.
I made my book with a three ring binder. Printing things is fine, but I find you learn and remember better when you write things by hand. It also makes your book more personal. That's just me though, to each their own.
I also have my very own, I made it myself the cover is of leather and pages are parchment paper is a little expensive,but is the way my Book Of Shadow that was handed to me from my ancestors is,I sew the pages together with leather strings, make holes with a hole puncher.
When I get stuck on a spell or on anything that I write I go to my old book.
