ACIM is a long tome, over six hundred pages. A chapter into ACIM the first thing that strikes you is "This isn't for everybody, yet it is!". If you continue after that seminal point to read it, you will learn a lot and there's a lot to learn but it becomes easier to understand as you go along and apply the exercises. Sort of goes like this:

     There is that which is always true, and what is always true is that the ego is false. This false 'guide', 'prophet', and 'wayshower' never includes, it only excludes, and eventually wraps that which is known as 'self' up into a tiny world of its own making. 
      Outside of that little world is everything else, everything else that exists, has existed, and exists past the end of time. 
     The mind is a powerful instrument, very fast in its calculations. It analyzes and projects, it takes in data and compares that with data that it has received before; its memory is vast, endless, it remembers everything. But where is it, and why is it? These are unknowns. 

     Because the 'I', the sense of self, can only be generally located, it is assumed by almost everybody to reside somewhere deep within the brain. The 'I' is never assumed to exist outside of the body, for outside of the body is 'other'.  
     So, there is the 'I', and there is everything else. 'I' against The World! 
     But, the 'I' is housed in a temporal thing, the body, which will eventually not be here so where does that leave the 'I' that you believe you are?
      Living in a fantasy world, a desperate world, a limited world, sort of like a transparent prison, where it can see the rest of the world but not inhabit it and this makes the 'I' very mad. Angry. Hateful. Jealous in the extreme. 
      Forbid access to the rest of the world, the ego can only hate and wish for death. The death of the weak and pitiful body, its prison, its 'home', but as it does so it also calls for its own demise, for when the body expires so does the ego. Back into the void it imagines it will hurtle, screaming like a banshee all the way and angry as hell, for it will have been denied life by the very 'god' that made it- itself! The ending to the ultimate horror film! 

    Ok... "Whew!" already! 

    The thing I like most about A Course In Miracles is that it doesn't mince words. It lays the reality of egoic thought bare on the table for the reader to examine and what is there ain't pretty to look at. Toughest love ev-er, this is, and it's necessary, because it's what is needed to break you out of the jail that you yourself created. 
     Because in the end, there are only two choices. Belief in the small, separate, pathetic, pitiful self, or acceptance of the reality of you as the Self, the whole, which is indivisible.  Forever joined you are in Reality, never separate. Separation from God was only a thought you had, a long, long time ago, and you believed it.

     But you can un-believe it. You can choose again. After all, that is what time is for. Time is given you so that you can decide which world you want to live in and it is known that when the last soul chooses to come home again the purpose of time will have been fulfilled.