Second Gear

My book, Invisible Driving by Alistair McHarg, a memoir of manic depression available from Amazon.com (www.invisibledriving.com) is definitely in first gear.  Since its publication a year ago it's sold copies around the world and been praised to the moon by Bipolar gurus across the country.  There are 40 reviews on Amazon alone, and it has an average 5 star rating.  But for some reason, the book has yet to accelerate, it is finding its audience very slowly.  Perhaps this is as it should be, I don't know.  I feel like somehow, someway I am missing that critical piece that will moves sales from first gear to second gear.  I am missing something.