This is a must read for all Christians.This can be easily read by Christians of all denominations.This book clearly outlines and clarifies Ignatius' fourteen rules on discernment with vivid examples.I wish I had this book when I first started out on my faith journey.The spirits here refer not only to the enemy-Satan and his evil spirits-but also to the human weaknesses and worldy attractions which can all impede the spiritual progress in a faithful person.I reccomend all the 4 books by Gallagher-he is truly an authoritative voice on the subject and he has definitely taken great pains to explain so clearly such a difficult topic.Here we get the advice that we must humble ourselves when given spiritual consolations and favors by our loving God and we must not despair when going through spiritual desolations-dry periods in prayer life and general discouragement when God withdraws his consolations momentarily.This cycle of consolations and desolations happen to every spiritual persons.Of all the rules,the most important one for me was not to make changes to our proposals-promises of actions,good works,ministries we vowed to God during our consolation periods or other times when we are confronted with dryness.Since this dryness is a trial and from the enemy,no matter what we feel at that time and our distrust in God,misunderstandings etc we should show our fidelity to our proposals.Ignatius has given us a wealth of information on how to discern this as well as God's Will in our lives in a solid systematic manner.A person who puts these rules into practice will surely progress leaps and bounds in his faith because now he knows the traps of the enemy and he prepares ahead.I was in a dry period in my spiritual life for a year or so and The Dark Night of the soul by St John of the Cross helped me white-knuckle it.But that book is a hard read and after reading this book,I think I did misunderstand certain points.I even thought that I would never ever receive consolations again from God and would forever be in a dry state.I really feared that it would end my faith life and I wouldn't be able to bear such a heavy cross.But the good Lord did give me consolations and favors when I was least expecting it,and once again gave me back a vibrant ,and joy filled spirituality.But now I know that dryness can occur from time to time,but I won't be so discouraged like before and with the help of this book,I know exactly how to go about it.After I am done with all 4 books(this one,the Spiritual consolations,Discerning God's Will,Examen prayer)I plan to go back and read The Dark night once again and clear out any misunderstandings I had.The difference between this one and Dark Night is that,Dark Night is dealing with a specific type of dryness or desolation,and the reasons why it might happen to us.But the part were what we need to do once we are in the Dark night wasn't very clear to me.It was Ignatius Rules which gave me that clarity.This book should be read in conjunction with Dark Night for a complete understanding of the spiritual dryness all faithful might encounter some time in their life.