i think that writers, artists, poets, etc... put a piece of their energy into their works, some shows more than others, some have an effect on the audience that is unmistakable and can be felt on a spiritual or emotional level. this is in everything we say, touch, do, act.. and even think. can it be felt more strongly in some individuals than others?, i dont know. but i do believe that we leave a piece of ourselves in everything we pass along. the interconnectiveness of the universe perhaps.... i dunno, this can open a discussion that has many many layers. but i do simply think that our writings, even across forums like this, along with our relationships with others (even digitally/electronically) can have an effect on our spiritual selves. as to whether a book can invite something in or have a negative outcome would make me question the writers intent and which side he walks.