Over the years I've been reading and reviewing books, I've come to appreciate just how much a good publisher can do for a book. Having the right author and the right material is essential, but a good publisher can make things really work.
There are lots of good publishers in the field of computing. Notable among these are Morgan Kaufmann, ddison Wesley and O'Reilly. These publishers seem to me to produce consistently good books. Not that others do not put out good books, but one of the things you notice is that some publishers are just a little bit less reliably good. And a few are even reliably poor.
How do these differences show up? The good publishers ensure that the material is fundamentally good: interesting, timely and on point. But even good material can be poorly presented and one of the jobs of a good publisher is to make sure that the material is presented well - this involves everything from checking the quality of the writing to good proofreading to making the typography and layout look good and to a good index. Even the good publishers sometimes goof a bit here, and mistakes are ok as long as the whole book works. A good publisher makes a good author look very good indeed, and can make even a middling author look good.
Other publishers (and I'm trying carefully to name no names) don't seem to care. At the worst there are a couple that seem interested in pushing almost anything with pages and a cover out their door. Sometimes the books are just silly, vanity press offerings but dressed up as something more (perhaps to get the author(s) publication credits). Sometimes the underlying material is good, but the publisher let the author down - not providing adequate proofreading, not working to ensure that the book is consistently laid out, not getting adequate technical review.
And then there are the money-grubbers. There are a couple of bottom feeder publishing houses who go that one step further down. I suspect they have academic and other large libraries who just gobble up whatever they print (I can't imagine why). These serve everyone poorly - the libraries use up their budget in buying junk, the authors look like idiots and the readers waste their time. Sure, one book in every dozen might be halfway okay, but the others are worse than a waste of money. I've read and/or reviewed more than a few of these. In one of the worst of these the authors started with material that was (at best) thin, wrote poorly (and clearly the publisher invested not one cent in proofreading), and wrapped it up in a $100 plus package that, and I can say this only of a very small number of the books I've reviewed, left me wishing I'd never even seen the book.I'll sometimes give books away on bookmooch- but I'd feel sorry for the person who got it - even free. A responsible publisher would have either just left this book to rot, or would have found a way to make the material more informative and interesting. I fault the authors for allowing the book to go to press, but I fault the publishers all the more.