I got into acting on a lark, as a hobby. I had been studying and auditioning for about three years with no success, and very little progress.
An instructor recommended this book. I read it, and then read it again. All of a sudden, things that had been drilled in my head during acting classes finally started to make sense. Within the following 6 months, my skills grew in a series of leaps, and I began booking at auditions. Not a lot, not yet. But the sudden increase in my abilities was astounding.
I am still not a great actor. But this book helped me get out of the "student" mode and into the "working" mode. Well worth it.
Outside of a masterclass with a Sanford Meisner-type or a Ute Hagen, this well-written, well-crafted book will teach you a tremendous amount in regards to make a character yours with little or no time to prepare. It will give you the skills to leave a lasting impression on casting directors everywhere.
Shurtleff's technique extends to once you have the role as well, preparation required to get the role will also assist you in making the role memorable.
It's also extremely helpful for screenwriters and playwrights, because it should give you insight on how to craft scenes for maximum impact by understanding how actors mine scenes for character, passion and emotion.