No, it’s not a typo, and it’s intended, although we don’t use this word because we’re not “Thelemites,” which is preferred by them (please google it, if you want to know more about it). The word magick was allegedly introduced and established by the Anglo-Saxon magician Aleister Crowley. It is a corruption of the original word magic, which means nothing else than “real” magic, so it is supposed to differ from stage magic and “pseudo images” by its unique spelling. In this respect, superficially, there is only a marginal difference between the terms “magic” and “magick.” Nevertheless, a clear distinction has emerged in the definition of these terms in magical usage, because nowadays magic is classified as conjuring tricks on a stage in front of a paying audience. But this has nothing to do with the magic we are practicing or is presented here – the magick. Therefore, magick should refer to a distinctive way to influence or change reality by magic, to receive information, and to call or banish forces! Also, magicians often call themselves magicians and not what they are: Illusionists (but “magic” sounds better more spectacular).