Spirit Guides are evolved beings, spirits who have lived on earth before. They have wisdom and experience to teach, inspire and guide us alon our journey.  They are teachers, guardians who work with us throughout our lives on earth.  Their primary role is to aid us in the process of developmental growth.  Their function is not to live our life for us, nor is it to answer all our questions, they are not "all knowing".  They are exactly what the word implies, "guides" who help us along the pathway of life.  Guides communicate with us all the time.  Speaking to us in many ways.  Sometimes its a very subtle voice in our head or thoughts.  Communicating to us through altered states of consciousness, through meditation, or in our dream state as we sleep.  Each one of us has a primary guide under whose care we are placed.  We are assigned a guide before we are physically born.  Arranging to stay with us throughout our lifetime to assist our spiritual path.  
Spirit guides are gentle, loving and have our best interests at heart.  Every avenue presented to us, is set up for us by our spirit guides to better our development.  Helping to remind us the lessons we mapped out before we came here.  The greatest gift we can give our guides for their support is a simple "THANKYOU"  Jenny48

Oh, cool. Very interesting subject. Thanks for posting this.