If you are thinking about making some shelves, this tool can save time and it does a great job. Look into the Kreg Jig K4 Pocket Hole System.
What a timesaver and it performs beautifully. For all those butt joints this could be your answer. I made some nice end tables. Look at the pics.
It works with many thicknesses from 1/8 to 1-1/2. Great for shelves, table joints. This end table was made from 2X4.