I have used this book at a college level and do not recommend it. The book is not clearly written and does not seem to follow a logical order. Unreferenced symbols are used in formulas throughout the book. Often, out of the blue, a statement such as a=xyz is made. In order to find out what a is, the user has to has to turn backward several chapters. All too frequently in derivations, a formula is referenced that is ahead in the text, or in a future chapter. Notation is also confusing in terms of symbol choice. For example, 'r' with a dot on top of it is used to denote the radial component of a position vector change. The reader is admonished to not confuse this with the velocity when a simple subscript could have sufficed.

I think this book is useful as a reference for someone who is already very familiar with the subject and does not need to understand how any of the equations are derived (because he/she already does.) And who perhaps needs algorithms for calculation.

For my work I needed to get up to speed on astrodynamics calculations very quickly. This book proved invaluable in that respect. I particularly appreciated the algorithms and examples that the author presented in addition to the usual derivations. The algorithms, in particular, proved very helpful in writing computer programs for my modeling and simulation work. I think that the material is readily understandable by upper level undergraduates in engineering, math, or physics. I also found the author's style enjoyable to read. There are numerous references for further study. I would recommed this book quite highly.