ePub book not showing up in iBook bookshelf on first generation iPad
Following @bmike's suggestion in a comment I tried copying the book from iTunes on my Mac onto my iPhone. That worked. Having established that the copy of the book on my Mac worked, I unchecked the book in the book synchronization tab for my iPad in iTunes, synched, so that the book was removed from the iPad, then rechecked the box and synchronized again. The book then showed up in iBooks and I was able to access it.