I've been thinking about this a lot and have yet to find said signature book for myself but the theory behind this gift is as follows: you think of a book that you love personally but has 'crowd favorite' potential (while still not a book that everyone has read or else why give book in question as present). The gift strikes a balance between giving something that is meaningful/personal to you while also giving a gift that they actually may like. This is not the sort of thing to give to close personal friends whom you know very well as you'd rather give them something that is tailored to them specifically, but is a great gift for people who do not fall in that category or people whom you are struggling to shop for. Again, I am still thinking about what my signature book will be but can imagine that once I find it, it will simplify gift-giving. Also you build aura as you give this book out consistently; it becomes strongly associated with you within the social circles in which you run (not that this should be the purpose of a good gift, just an added benefit).