I ask again; so do these books work? Yes. Allow me to focus momentarily on the Grand Grimoire. This book, so it's believed, originated during 13th century Egypt written, or translated from an older source by a man known only as Alibek. The book is said to have instructions to evoke Lucifer for the only purpose of forming a pact with him. Now there's a problem here. Lucifer isn't an Egyptian spirit. The name belongs to the Greeks. Again we can see the Church's influence This book is best known in it's Italian version translated by Antonio Venitiana del Rabina.
During my early 20's I was fortunate enough to get my hands on the Lemegeton written in Crowley's hand. It cost me more money than I could afford but it was well worth the price. It had taken me five years to find a copy of the Goetia. If the internet had existed back then I would have found the book immediately. Finding an entire copy of the Lemegeton from which the Goetia was one fifth of it's writing was like finding King Solomon's gold. This book, which included Crowley own scribbling was priceless.
When speaking of Grimoires the Necronomicon always comes into the conversation. Although this book was first mentioned by H.P. Lovecraft many people believe this book to be authentic. I don't share the same belief. Pay attention to the symbols used in the Necronimicon. They're too similiar to the scripts, Passage du Fleuve & Malachim, which were both a creation of Agrippa during the 16th century. The seals in the Greater Key of Solomon also have these scripts. I'm starting to wonder if Agrippa had anything to do with the development of the Greater Key but I don't want to start any rumors here. Whomever wrote the Necromomicon used these two scripts for inspiration. Although the book is a work of fiction the Spirits mentioned within its pages can be evoked. How is this possible? Even if the Spirits are made up which I'm sure they are life can be given to the energies. If you've ever worked with the Necronomicon Spirits write me. I'd like to hear your experiences.
Many of these Spirits were invented or are permutations of ancient Gods. It's the energy placed upon them which is important to their existence. If you take the Necronimicon you will without a doubt fail to evoke any of the Spirits mentioned therein unless through proper meditations and telematic imagery is placed upon them. Keep in mind that the Grimoires will affect you on a mental level so care must be taken when working with these Spirits so if you're weak minded then do not dabble with these books. In my own workings I've been confronted with frightening things. Some do appear with a thunderous motion.
One final thing must be said of the Grimoires. When working with these books keep in mind that information changes with the times. If the Greater and Lesser Keys were truly written by Solomon then the Church's influences during the medieval period would have corrupted the original text with their own personal superstitions. You can do one of two things here. Add your own beliefs in order to make the Spirits move or sift through the bullshit (yeah I said it) and find the root source of all information.