I've been reading a bunch of books on this topic lately, and this one is excellent (you wouldn't believe how bad some of them are).
It is fairly dense and not childish or cute at all. But it is very well-written, with each sentence saying what it says, and the next sentence saying the next thing that should be said.
Those of you looking for that rare book that is smart but accessible should give this one a try. I get the impression that if you got a sales management job, took a copy of this book to work, and just did what it says to do, every day, you'd be well above average at your job.
*******
Postscript to McGraw-Hill: The awful cover illustration probably cost you thousands of sales. This book is NOT about a guy with a tiny head standing at a cash register, glowing or otherwise. Your audience for Sales Management books is NOT guys with tiny heads standing at cash registers, glowing or otherwise.