I've always been inclined to assume that I have never seen a unicorn, but I hadn't even finished reading the introduction when my assumption was challenged by a simple question: "How many bird watchers have spied a warbler perched upon a tapered branch, never dreaming that the selfsame branch is, in actuality, a unicorn's horn?"

It's a problem. Vision is an unreliable tool under the best conditions, and as the author points out, "there are great odds that a unicorn will approach from one of your many blind spots." This, of course, to remind us that the most troublesome blind spot of all — in the center of our field of vision, where the optic nerve is connected — is filled in by the brain. Thus, the mind that rejects the existence of unicorns is unlikely to fill that empty optical space with a unicorn.

This leaves sound as the only reliable ally. More than a collection of unicorn-sound waveforms and beyond its value as a compendium of unicorn knowledge, the book calls on us to stare with our ears, as Ken Nordine intended.

"My unicorn can whisper strange things when I want him to, and sometimes when I don’t." —Larry Niven, as quoted in A Field Guide to Identifying Unicorns by Sound