My bookshelf was ticking this morning. A very fast tick. Haven't worked out what was çausing the ticking. I said to my son it could be a bomb, but it never went off, I also said maybe it's some kind of device which is spying on us. I went over to the book shelf and put my ear to each level and could only hear it in the middle shelf, same with my son. I have taken all the books out, swept/dusted and looked at middle shelf, went through each book (30 - 50 of them) and found nothing. I'll do the other four shelves another time. My son suggested the ticking was coming from behind the bookshelf or garage. But I can't even squeeze a finger behind the bookshelf. I doubt anything would be behind it. And I can't be arsed taking all the books down to move the bookshelf to look, one shelf at a time is hard enough. And if it was coming from the garage I'm sure the noise wouldn't be specifically heard in one part of the shelf??