Two of my recent publications deal with the topic of salvation theology. The brief booklet:
Heaven, Hell, Purgatory, and Limbo
explains those three places and their role in the plan of God for salvation. The booklet starts with a summary of the Catholic view of Purgatory, something Protestants generally deny. The next chapter summarizes Catholic teaching on Who Goes To Heaven, and then describes what Heaven is like. Hell and Limbo are then dealt with in the remaining chapters.
For a more comprehensive explanation of Catholic salvation theology, see my book:
Forgiveness and Salvation for Everyone.
This book presents a moderate view of salvation theology. I argue against the liberal idea that nearly everyone is saved, and against the conservative idea that nearly everyone goes to Hell. Salvation is available to all human persons, including non-Catholic Christians, non-Christian believers, and unbelievers. The only persons who are sent to Hell are those who are unrepentant from actual mortal sin.
It will be interesting to see what Pope Francis will teach on salvation theology. He has made comments, so far, indicating that atheists may be saved (perhaps without formal conversion). He seems to favor a view of salvation theology similar to my own. But we won’t know for sure until he publishes a document of the Magisterium on the topic.