I'd go further than that: most books probably go out of print after a single run, and will be unavailable within a single year. Remember that when you go into

I'd go further than that: most books probably go out of print after a single run, and will be unavailable within a single year. Remember that when you go into a big chain bookstore, all the books you are seeing have already outperformed most by getting shelved by a major retailer.