You can put a book on a table with part of it over the edge. As long as enough of the book is on the table, it will not fall. How much is “enough”? Just the tiniest bit more than half.

Now we can pile two books on the table so that the top one extends over the edge by more than half its length.

Is it possible to stack more books in this fashion so that the top one is fully beyond the edge of the table? If it is possible, how many books do you need?

First take a guess. Then try it. And finally, give an explanation of your result.

Then, you can check our solution.

Thanks to David Tempel for suggesting this puzzle.