From a work-related E-Mail correspondence regarding a very large graduate-level textbook named "Atmospheric Chemistry and Physics" by John Seinfeld & Spyros Pandis):
F.: I returned your copy (after a long time, for which I apologize).
M.: Actually, now I’m baffled. I borrowed what I thought was my copy from W., and so now I have two copies. But I know I have just one book.
F.: How interesting. I'm actually returning your copy now because another showed up in my office, so I no longer need this one.
M.: The volume is so large it contains within itself the genetic information for its own propagation.