The best known of the interference paradoxes is the double slit. How can successive quantum particles passing through the slit system and later detected at specific points in the interference zone build up a pattern showing interference of a sort that depends on the separation of the slits, even though measurements carried out directly behind the slits will show that the particle passed through one or the other, but not both? Feynman’s discussion (Feynman, Leighton, &amp; Sands 1965: Chapter 1, where two holes replace the two slits) is superb. What is essentially the same paradox, but in a form somewhat easier to analyze, is the one in which a particle passes through the two arms of Mach-Zehnder interferometer. Chapter 13 of Griffiths (2002a) provides an extensive discussion of how the histories approach deals with different possibilities in a consistent way that avoids paradoxes while producing analogs of all the interesting effects discussed by Feynman.