I write nearly all the proposals in the company I work for, a mid-sized web design and internet marketing agency. While not strictly a consultancy, we do a LOT of consultancy-type work, and unless you want something really defined and specific ("Get me a 30-second Flash banner now!") we always have an element of consultancy in our contracts.
This book is our pricing and proposing bible. Its stated aim ("Million Dollar Consulting") forces you to think about value for your client, shape what you do around providing that by giving them superb work, and then charging appropriately for it. By making you consider the VALUE of what you do for your clients, and putting metrics in place to measure this, it allows you to pitch your charges relative to what your work is actually worth. They get great service and a much improved situation, you get paid well. It's a win-win.
Of course, doing all of this for real is harder than it sounds, and that is where our copy is really getting dog-eared: At the setting fees, conducting client consultations, and writing proposals part. By structuring the lead process properly, we are closing more and delivering better proposals, and we also know we're delivering better services at the end of it.
Only irony is that as the book is many years old, the web section raises a few sniggers - though actually, the author is on the button saying that websites must be genuinely useful, email newsletters must offer non-commercial content, and that the web is growing in importance. Still is.
While it tails off a little towards the end and a few pages are not relevant to non-US (or non-"pure consultancy") readers, I really recommend this book to anyone in any line of work where consultancy plays a role and where proposals are written to gain contracts.