I stumbled on your 'book' while searching related topics on the Internet. I 'opened' it, as a relatively open-minded liberal, well disposed against what you're a proponent of, but therefore curious.
I have a couple of quick comments, and then wish to refer you to an argument against your point of view, which I've written up hastily in a kind of compressed shorthand on my blog. I'd be interested in your feedback.
First: I think you make the mistake many people do of assuming that breeding mimics evolution. The variety among horses (or dogs or goldfish) involves no speciation, and pretty much by definition can't, since "breeding" means within breedable partners of the same species.
Breeding in fact creates instability in genotypes by loading up the pool with non-randomly distributed traits, by definition divergent from their environmental ground, creating a population which must be artificially cared for, much like any diseased population. So the changes depend on the stability of the breeders' preferences . . .
And there's recent evidence for a quasi-Lamarkian inheritance of acquired characteristics (involving the folding rather than encoding of genes, at least metaphorically, by a kind of "epigenetic" process), placing these variations within the realm of phenotypic rather than genotypic variation, but heritable nonetheless. Breeders' decisions do not constitute an analog of 'environment', which is the full ground without which genetic codes (as figure against that ground) are 'meaningless'. It is environmental drift which "directs" evolution, and (apparently) random couplings in response, not artificially altered directions.
Second: You utterly ignore and bypass, so far as I can tell, the plain fact that the ability to render acceptable and moral political consensus is obstacle enough to prevent the effort. The chances of a non-corporately dominated direction for our guided evolution are practically nil. And whether it's Mao, Stalin, Hitler or Coca-Cola, they're all sociopathic in their intents. Corporations should never have been given status as legal persons. And governments should learn to act as other than self-preserving corporate entities too, for that matter. Changes to our political ground will stimulate "proper" evolution more directly than will directed choice in mating.
In the end, I think you're wrong to think we're NOT still evolving. Our locust-like social behavior practically guarantees that, through the mechanism of punctuated equilibrium (cataclysmic change favoring oddball survivors), the current species will not survive the destruction of its (and every other creature's) environment. What will survive, if anything, cannot be known in advance.
Indirectly, of course, you are absolutely right that we *have* been conducting a great eugenic experiment, which is why we've overrun the earth like the swarm of locusts that we seem to be. We've taken control of the environment (sophomorically speaking, we've created an artificial environment) and it's that fact which has halted evolution in your eyes. More artifice in the selection process will simply pound the cork into the bottle and that will be the end of man.
Well, I guess the end of man could be the beginning of what comes next, but I'd hate to construe that along the lines of what we now call "intelligence" so crudely measured that it isn't even more heritable from a man to himself (.8 correlation across tests for the same individual) than from that same man to his offspring. Intelligence, my friend, like beauty, is in the eye of the beholder, though no less real for that.
All the best,