Breslov Research Institute has recently published a new book by Chaim Kramer called The Potency of Prayer. Here is a bit of the description of the book from BRI’s website:
The Potency of Prayer, based on the teachings of Rebbe Nachman of Breslov (1772-1810), a leading Chassidic master, and his closest disciple, Reb Noson (1780-1844), offers a comprehensive explanation of the daily prayers, including Shabbos, Rosh Chodesh and Festivals.By reviewing the entire Siddur, The Potency of Prayer delves into the reason behind each prayer and explains how the prayers are interconnected. With a blend of straightforward commentary and Kabbalistic insights, you will discover the power that lies behind the words and realize the potency of your efforts.
Buy it here – https://books.breslov.org/product/the-potency-of-prayer/