Books on Consulting

Any recommendations for books on consulting?

I'm considering entering into a consulting arrangement with a medium sized private company -- I've never formally worked as a consultant before -- and could use some advice!

I'm a big fan of David Maister (The Trusted Advisor, Managing The Professional Service Firm and Strategy and the Fat Smoker: Doing What's Obvious But Not Easy) and Charles Green (The Trusted Advisor and Trust-based Selling: Using Customer Focus and Collaboration to Build Long-Term Relationships) but I'm looking for more practical / how-to / nitty gritty books.