The objective reality of ideas play san important role in the cartesian system, for upon it rests the whole force of his demonstration of the existence of God. Ex hoc (idea entis summe perfecti) enim uno tot avis demonstrationis meae dependet. Not only does the demonstration of God's existence take its point of departure from the objective reality of ideas, but it is an axiom that the knowledge which we have of all things, sensible and insensible, rests on the objective reality of our ideas and on the application to it of the causal axiom. Omnia enim diligentissime circumspexi, et nullum aliud argumentum potui hactenus reperire. Important as this position is in the cartesian system for the reason that the actual existence of beings other than the thinking substance can be demonstrated only by beginning with the objective reality of ideas, still this docritrine was the cause of surprise and of many objections from his contemporaries. Descartes admits that the author of the first set of objections puts in brief compass his own argument for proving the actual existence of God, and, having indicated his assent to that which he thinks is clearly enough demonstrated, comes to the crux of that which is difficult in the demonstration.
This book breaks down the three proof's for God's existence as described by Descartes in his meditations. The third meditation proof and the sixth meditation have the most focus.
This was used mainly as reference when you need some shot-gun power as to the logical details and steps for the flow of each argument. The reference I used this for was, God keeps us existing in the line of thought: Descartes is certain he thinks, the forms exists, something caused that, God exists, God keeps us existing. That is explained over three-hundred or so pages. I did not get into suarez.
The book is logically laid out very well and covers different senses of each word and addresses every concievable problem that arises.
The contents page will guide you exactly where you need to go. Each chapter is laid out with precision. You may need to read this early in the day or when not tired and I recommend being well fed, so clearly we exist, because we ate.