floats versus doubles

When to use floats and when to use doubles is one of those classic topics of discussion and much less pointless than the code formatting religious fights.   A fun thing in the new edition of FCG is that Steve Marschner and I are in opposite camps.   I just checked what amazon previews to the reader with "look inside" and found this (note-- I think that discussion of debugging is something I wish I could send back in time to myself-- it's VERY basic but graphics debugging is different in some ways):

Screen capture from Amazon preview of Fundamentals of Computer Graphics 4th edition

See-- sometimes opposing camps can get along :)