This book easily stands alone, but makes slightly more sense if you've read the previous two.  Ransom, the protagonist of the first two books, is in this book as well but he's not the protagonist.  Lewis once again seeks to recast Biblical themes in terms and conditions that are recognizable as part of a modern (philosophically as well as historically) world.  What might the struggle of good against evil look like - or more accurately what does it look like?  What tools would be utilized?  What strategies?  Lewis further makes an interesting twist in linking some of those stories and myths of our world and suggesting that they bear witness to angelic & demonic forces at play in our ancient past.  While it's difficult to say if this is something that he firmly believed or just an idea he was toying with, it makes for a fascinating idea, that of two realities and identities at struggle culturally as well as individually.  Saint and sinner motifs on a societal level, so to speak.

This book asserts ultimately diabolical ends to many of the scientific and technological means that portions of the Western world is obsessed with.  What lies behind the redefinition of humanity as first an animal, and next just a collection of cells?  What purposes could be had to stripping people further of their gender and sexual identities in preference for a generalized person-ness?  Fascinating questions in our society today.  Lewis clearly saw the direction Western culture was heading, and hypothesized as to the spiritual forces at play.  It would be interesting to get Lewis' take on where we stand today and where we're headed.  I imagine that he would simply say "I told you so".  

This book is frightening on several levels.  First of all, it tends to reveal in the reader how far down the slippery slope they likely have gone in terms of 'modern thinking' or 'modern sensibilities'.  Secondly it reminds us just how vulnerable we are to media manipulation.  While the age of more egalitarian communication has arrived, for the most part what we read and ingest is provided to us by people we don't know and never will know, and whose motives we ought to be very cautious of.  Thirdly, it demonstrates our technological vulnerability, as well as our vulnerability to experts.  We live in an age where much of our right to self-determination and individual thought is limited by the idea that only experts are qualified to do thinking or acting in certain realms.  We sit and wait for pronouncements, stamps of approval, and sometimes vilification and even legal actions from those who sit in self-pronounced authority in literally every arena of life.  Common sense is uncommon and viewed as generally untrustworthy compared with the impressive sounding degrees and pedigrees of those who claim to know better about how to rear our children, how to express our sexuality or other core aspects of our identity.

I strongly encourage people to read this book.  It will make you think.  It may make you worry.  But it provides a way of linking the ideas we see in Scripture and Christianity with the world we live in today.  They are not two separate worlds after all, and Christians would do well to remember that - so would the Church.