I've been looking for a book like this for 5 years to help me understand better nonlinear regression. The only choices before this were the same old basic stats books, or the other extreme of stats books for mathematicians. As an engineer, I needed a book that does APPLIED, not THEORETICAL, nonlinear regression. This book gives examples and speaks normal English, unlike Seber and Wild's book, which is virtually devoid of examples and drowns one with matrix math instead. Seber and Wild's book is more like a dictionary of stats equations. For Motulsky's book, here are 3 examples of things you won't find in most other statistics books: 1) the difference between confidence bands and prediction bands for Y(p. 32), showing that the former doesn't include a majority of the points, while the latter does; 2) How to compute egg- and elliptical-shaped joint confidence regions for 2 parameters (p. 114-121); 3) Good explanation of 3 different ways to compute parameter conf. regions (asymptotic, Monte Carlo, model comparison). Just one of these 3 makes it worth the price of the book for me.
Motulsky has so many different helpful topics in here, that he obviously has run into many of the problems that nonlinear regression people will see. The book is helpful regardless of the software you use, because I do a lot of coding in Matlab. I may make this book a standard text for a new engineering statistics class I am preparing.
The main shortcoming of the book for me (remember that I'm an engineer) is lack of the exact equations 1) for confidence bands and prediction bands for Y (p.32), 2) for asymptotic conf. interval for parameter (p. 98), and 3) for standard error vs. standard deviation. For the first 2, the author could reference eqn. numbers in Seber and Wild or Bates so his text flow would not be interrupted. For those of us who publish, we need to know what's going on in the black box. The standard error/standard dev. formulas would make the explanation given easier to follow.
In summary, this is the book that will help walk you through many of the problems and concerns in nonlinear regression. I'm glad someone who understands my situation finally wrote it!