To view the Max help file on Shadow types, use the following link -
http://docs.autodesk.com/3DSMAX/15/ENU/3ds-Max-Help/index.html?url=files/GUID-CB5F2A06-B774-4F27-9FDE-DE4926BE847C.htm,topicNumber=d30e344426
...alternatively click HERE if you're super lazy...
This is even better!
This is the CG Lighting book
http://books.google.co.uk/books?id=KIfOAwAAQBAJ&pg=PA54&lpg=PA54&dq=different+types+3ds+max+shadows&source=bl&ots=iTCAwWObR-&sig=jAWONnJzWpuNahJ8NJPT7nfv0sQ&hl=en&sa=X&ei=nX03VNbHCdDgasX2gagG&ved=0CEUQ6AEwBw#v=onepage&q=different%20types%203ds%20max%20shadows&f=false
