RängeMeister is based on the theory that good players are effectively able to leverage previous experience to come up with good estimates to answer these questions. The objective of RängeMeister is to help players evaluate situations that they've found themselves in by listing similar hand histories as well as the relevant data from these hands.
Using RängeMeister is simple; you just select a marked hand or paste a hand history into the input screen just like you would if you were about to post the hand in a forum. Then you play the hand in the replayer until your desired starting point and click the refresh button. RängeMeister will then find all the hands that played similarly up till that point and display them in a grid.
You can either study these hands yourself or move over the to the "simulation" tab. This complicated screen allows you to view things like what your opponent's range looks like and how he will react to the different actions you may take. At any time you can play the similar hands in the replayer.
RängeMeister won't tell you what the right play is but it will estimate equities based on hand ranges and allow you to make the decisions more intelligently and not based on emotion. Use RängeMeister to plan out strategies for situations like blind steals/defenses, light 3 bets, floats, and any other scenario you can imagine. If you're worried about playing against certain player types (LAGs, TAGS) RängeMeister lets you filter for that and just about anything else!