I'd suggest checking out [https://www.amazon.com/Understanding-Controlling-Stuttering-Comprehensive-Hypothesis/dp/1929773242](https://www.amazon.com/Understanding-Controlling-Stuttering-Comprehensive-Hypothesis/dp/1929773242). I've compared notes with someone who had gone through the McGuire program and it seems quite similar, with the key difference being that the Valsalva Method really emphasizes relaxed breath with a focus on phonation / vowel sounds. I started this self-help program in 2015 and it inspired me to create [FluencyShaping.com](https://FluencyShaping.com), a practice tool that is strongly aligned with the exercises and techniques outlined in the above book. Hope this helps!