Grail to me has always meant first a chalice or cruet in which Joseph of Aramathia caught the blood of the crucified Jesus in European Christian legend, and second, a sort of dish that is always full of food from some older Celtic legends. HB, HG is a fun read as long as you don't take it too seriously. The authors play pretty fast and loose with history, and the border between their imagination and history and even legend is pretty fuzzy. I enjoyed it the same way I do various conspiracy theories of history and/or UFOlogistical books: i.e., as a genre of fiction. There is a Yahoo Group that is dedicated to the book and its sequels. [NB: The above is the opinion of a secular humanist and is not meant to disparage anybody elese's beliefs.]