They waited for five hundred years before taking action. Perhaps they delayed out of precaution or in the hope of finding some other way. Or maybe time counts differently for them. For a life stretching into infinity, time hardly has any value. During all these five hundred years they watched us, studied us. They read our brains, absorbed our thoughts, dug into our knowledge, absorbed our personality. They probably know us better than we do ourselves. What is their clumsy imitation of our thoughts? Just a trick, an attempt to make us think they are harmless? Or is there the same difference between their imitation and our thoughts as between a parody and a real work of art? Until now we have not tried to defend ourselves against them, since we considered them funny creatures and nothing more. I am convinced that they will make new attempts, even if they have to wait another five hundred years. Therefore, I insist that every effort should be made to invent effective weapons. But we will use it only as protection. There can be no talk of extermination, such as was carried out on other planets. But for this we must study them the way they studied us. To fight them, you need to know them. Next time they will undoubtedly come up with a new method of attack. It is also necessary to develop a system for checking everyone entering the Station in order to determine whether he is a person or a Shar. And, finally, every effort should be made to provide ourselves with some other source of energy in case Mercury becomes unavailable to us