An intelligently laid out and accessible manual, designed to review and highlight the sorts of skills a professional coach should be able to display to do his/her job effectively. When it comes to an analysis of practical skills - such as establishing the context for coaching by using comfortable, conducive space, defining expectations, setting the ground rules for contact, etc. - Julie Starr offers excellent, coherent advice.
The weakness of this manual - and any such manual - is in the areas of philosophy and skills training. In the former case, coaching (or, indeed, therapy or counselling) must begin from a position of respect for the individual. More particularly in coaching, the objective is to help the client (or "coachee"), achieve change, achieve goals by internalising the objective and finding their own way there ... rather than being obviously directed by the coach. Teaching people respect for the individual, teaching them objectivity, teaching them that level of empathetic detachment, etc., is not easy, and I have my doubts it can be accomplished simply by using a manual.
Similarly, there are very real skills which come from experience and critical awareness of your own practice. You can tell people how to listen, how to ask open-ended questions, how to feedback objectively, but these skills (and many others) need to be practised and learned through interaction in the field. At very least, you need to role play the skills.
Starr's manual is excellent when it comes to the practicalities and the applied psychology of the professional relationship, but other aspects are decidedly weak. This is most obvious in her chapter on the fundamental skills of coaching: she identifies five core skills - building rapport or relationship, understanding the different levels of listening, using intuition, asking questions, and giving supportive feedback.
Now, I've worked in social work and research for a quarter of a century: I use the five skills identified above ... and I'd recognise their validity in any form of motivational interviewing or coaching. But I'll stake my pension on the fact that you can't learn intuition from a manual.
Julie Starr's "The Coaching Manual" is an excellent book, and good value. She communicates well, her writing is intelligent, accessible, and she makes some excellent points. However, to get the best from this book you should consider working with other would-be coaches or others interested in the subject - maybe role playing some of the themes to give yourself a chance to evaluate your attitudes and communication skills. Experience is an essential skill, one which is acquired, not learned. What the manual can't give you is a critical feedback on your own performance and the adequacy of your own experience and current range of skills. If you are going to be a good coach, a really good one, and not just delude yourself that you know what you're doing, you will need to supplement this manual with a deal of practical experience ... and some objective self-criticism.