If you’re actually working for a company as an employee, there are several ways you can approach this. The first is to pitch this as an outside project, over and above your day job. I don’t recommend this! Unless you’re young and in good health and really like chronic sleep deprivation, this is a Bad Idea.
As I’ve mentioned in previous posts, writing a book will be the single biggest professional undertaking in your career to date. If this is your first book, you just have no idea how much work this is going to be. And if you’ve written books before, you’re still not figuring on how difficult it is doing a fulltime job in the day and then trying to put in another 6 hours of writing at night. You get pulled in multiple directions and that’s even assuming that you’re going to be working only a 40-hour week at the day job. (The only writers I know who end up working 40-hour weeks are hourly employees with tight overtime restrictions.) Your work in both venues will suffer, so don’t do it. Lay out for the company just how much time and energy it takes to write a book. Treat it like any big project and don’t let them whittle you down. (Use the facts and figures in the previous series of posts about the likely timetable.)
Now, you might be able to do something if you a guarantee in writing that you’ll be working half-time while you’re doing the book. I did this once when a database company I worked at was going through a cost-cutting phase and tried to get everyone to take a salary reduction (basically because the guy who ran the company was a fool who thought he knew how to manage money). I went half-time for several months and wrote a book with the other half of the time.
If you work for a company, I suggest that you pitch the idea of a book this way: you write the book. You get assigned the task of writing the book as your official job. You get your normal wages. You also take care of coordinating things with the publisher and doing all the legwork to set up the deal, and you get the royalties as described in the previous series of posts.
Typical questions and answers are:
Q. Why should we pay you a salary AND royalties?
A. First, because this requires special skills that are far above what you normally have me do here for salary, and second, because this will be more than an 8-hour day, particularly at the end of the process. I will definitely be earning the royalties. [Note: you really will, I promise. This is going to be grueling.]
Q. Why shouldn’t we get someone cheaper?
A. You can always get someone cheaper, but the value of having me do it is that I already am heavily familiar with the product I’m writing about and I know where to go for all the internal information. Any other author you get, even if they’re local, will not have the product history I do nor the knowledge of the people in the company. Expertise is not something you can pick up overnight. Also remember that I have product knowledge, I know how to put the publishing deal together, and I have the internal company contacts. Each of these skills can be found elsewhere, but it’s very difficult to find all three of them in one person. And if you do find them, it’ll be clear to them that you need them very badly, so their price will probably go way up. The bottom line to all this is the bottom line: you’ll get the book you want faster and better with me than with anyone else.
What I’m describing is going to require a fair amount of negotiating skill on your part, but it’s worth it. And FWIW, this is no worse than the negotiating you need to do with publishers if you don’t have an agent. Don’t doubt me when I say that you’re going to earn all the money. It’s an awful lot of work you’re setting up for yourself.
It’s possible that you’re going to deal with management that’s too cheap to want to pay you anything other than your salary. At that point, look at the deal and ask yourself how much writing a book is worth to you professionally. Be prepared to walk away from the table and say “No, this is way too much work and I’m not going to do this for just my salary. Thanks all the same.” (I’ve done this on book deals: if the money’s not good enough, I’ve told them that I don’t work for that little.) In particular, get a signed deal that you won’t be working more than 40 hours a week: books can easily become The Job That Ate My Brain.