If you are interested in some of the Gestalt related books that inform the way I think about therapy, below are a list of books that I have found helpful.
Gestalt Therapy Integrated - Erving Polster. This is a classic Gestalt text. The chapter on resistances is a stand out chapter.
Gestalt Reconsidered - Gordon Wheeler. While Wheeler's writing is dense and takes some time to digest, he has offered a lot to help Gestalt theory evolve. Of note is his chapter on reconsidering resistances as contact styles.
Body Process- James Kepner. This classic text describes The Cycle of Experience, maps the resistances/contact styles onto the Cycle of Experience, and underscores how embodiment is relevant to well-being.
The Spell of the Sensuous - David Abrams. One of the three pillars of gestalt theory is phenomenology. The chapter reviewing Merleau-Ponty's work is probably the best and most user-friendly reads on phenomenology that I've come across.
A Well-Live Life - Sylvia Fleming Crocker. This is an excellent collection of essays about Gestalt theory. Essays II and II were the most noteworthy reads. They do a good job of highlighting the wisdom, health, and adaptive nature of our resistances/styles of contact.
The Voice of Shame - Robert G. Lee. Chapters 1 and 2 of this book changed the way I understand what shame is and are noteworthy.
Gestalt Therapy: 100 Key Points - Dave Mann. This is a good introductory text to gestalt theory. The chapters are short and easy to digest.