Behind the Perry Approach are decades of reading, researching, applying, and — only now — codifying. The works gathered here are the ones that shaped it along the way: some gave it structure, some gave it language, others simply changed how Karl saw the problem. Many more left their mark in ways no single citation can capture. What unites them is that they were never just read — they were tested, in real organisations and against Karl's own conflicts, and what proved itself in practice was kept.
This is a living list, organised by theme rather than alphabetically, so you can follow the lineage of ideas rather than hunt for names. Where a work is referenced inline in a particular chapter, that connection is named here. It grows as the book grows.
Theory of Constraints
The intellectual foundation of the Evaporating Cloud and the Perry Approach.
Goldratt, E. M. (1984). The Goal: A Process of Ongoing Improvement. North River Press.
The founding text of the Theory of Constraints, introducing the idea that every system is limited by a constraint, and that the work of improvement is to find and unlock it.
Goldratt, E. M. (1994). It's Not Luck. North River Press.
The sequel to The Goal, and the place where Goldratt demonstrated — in Chapter 17 — that the Evaporating Cloud could be applied to personal as well as business conflict. The structural source of the Perry Approach. Referenced in Chapter 2.
Goldratt, Efrat (1995). Embracing Change vs Resistance to Change: The Causes for the Conflict. Goldratt Marketing.
The paper in which Efrat Goldratt (later Goldratt-Ashlag) first examined why the same person can want a change and resist it at the same time — the security–satisfaction tension that underlies all human conflict, and the second pillar of the Perry Approach's genesis. Referenced in Chapter 2.
Mabin, V. J., Forgeson, S., & Green, L. (2001). Harnessing resistance: using the theory of constraints to assist change management. Journal of European Industrial Training, 25(2/3/4), 168–191.
A re-examination of the conventional, negative view of resistance to change. Mabin and colleagues argue — and demonstrate through a bank-merger case study — that resistance is a necessary and positive force, and that the Theory of Constraints provides tools to harness it rather than overcome it. This sits at the heart of the HPtE conviction that conflict is a source of performance, not friction to be reduced.
Mabin, V. J., & Balderstone, S. J. (2003). The performance of the theory of constraints methodology: analysis and discussion of successful TOC applications. International Journal of Operations & Production Management, 23(5/6), 568–595.
Victoria (Vicky) Mabin, Emeritus Professor at Victoria University of Wellington, conducted a meta-analysis of more than 80 documented TOC applications — the empirical backbone showing that the methodology delivers significant operational and financial improvement, with no reported failures found across an extensive search of the literature. Her research and teaching brought academic rigour to the Thinking Processes. Acknowledged in Chapter 2.
Cox, J. F. III, Mabin, V. J., & Davies, J. (2005). A case of personal productivity: illustrating methodological developments in TOC. Human Systems Management, 24(1), 27–39.
A worked illustration of the TOC Thinking Processes applied to an everyday personal problem — productivity — using the Evaporating Cloud together with the Current Reality Branch and Future Reality Branch. An important precedent for the Perry Approach's use of the cloud on personal as well as organisational conflict.
Goldratt, E. M. (2009). Isn't It Obvious? North River Press.
A business novel applying the Theory of Constraints to retail. The source of Chapter 1's point that the informal system — the relationships, the friendships, the unwritten rules — is what truly makes an organisation, more than the formal system ever does. Referenced in Chapter 1.
Goldratt, E. M., & Goldratt-Ashlag, E. (2010). The Choice (Revised ed.). North River Press.
A later, more reflective work on clear thinking and the assumptions that hold us back, written as a dialogue between Goldratt and his daughter Efrat. The source of Goldratt's statement of his foundational beliefs — “every conflict can be removed … every situation can be substantially improved; even the sky is not the limit … there is always a win-win solution” — which captures, in his own words, the conviction underneath the whole Perry Approach. The revised edition adds Efrat's Notes: her own logical maps of the dialogue. Referenced in Chapter 15.
Goldratt-Ashlag, E. — writing on the psychology of resistance and change in Theory of Constraints practice (see her contribution to Cox, J. F., & Schleier, J. G. (Eds.), Theory of Constraints Handbook, McGraw-Hill, 2010).
Efrat Goldratt-Ashlag carried the cloud into the psychology of change, articulating the tension between our need for security (confidence in the reliability of our predictions) and our need for satisfaction (a sense of achievement) that underlies all human conflict. This is the second pillar of the Perry Approach's genesis. Referenced in Chapter 2.
Gupta, M. C., Boyd, L., & Kuzmits, F. E. (2011). The evaporating cloud: a tool for resolving workplace conflict. International Journal of Conflict Management, 22(4), 394–412.
Mahesh Gupta and colleagues set out, with a worked case, how Goldratt's Evaporating Cloud maps onto the language of interest-based problem solving — surfacing the conflicting interests that sit beneath entrenched positions, making the hidden assumptions explicit, and challenging them to reach win-win solutions. The academic grounding for reading the cloud as an interest-based engine. Referenced in Chapter 2.
Negotiation and interest-based problem solving
Where the cloud meets the language of principled negotiation.
Fisher, R., & Ury, W. (1981). Getting to Yes: Negotiating Agreement Without Giving In. Houghton Mifflin.
The founding text of principled negotiation and Interest-Based Problem Solving (IBPS): separate people's positions (what they say they want) from the interests sitting beneath them, then build agreements that serve those interests rather than bargaining over positions. Chapter 2 draws the line from IBPS to the Evaporating Cloud, which maps onto it almost element for element. Referenced in Chapter 2.
Philosophy of inquiry — abduction and the Evaporating Cloud
The deeper lineage underneath the question what other way is there?
Andersen, S. S. (2024). Unveiling the intellectual nexus between Peirce's synechism and Goldratt's Theory of Constraints. Journal of Management History.
Andersen traces the philosophical line from Charles Sanders Peirce — who coined the term abduction and placed it as the engine of all inquiry — through to Goldratt's Theory of Constraints. The abductive structure underneath the cloud method, and the Chapter 11 question what other way is there?, sit within this lineage. Referenced in Chapter 11.
Andersen, S. S., Gupta, M. C., & Gupta, A. (2013). A managerial decision-making web app: Goldratt's Evaporating Cloud.
An earlier paper engaging directly with the Evaporating Cloud as a managerial decision-making tool. Useful background for readers interested in the academic engagement with the EC.
Meaning, agency, and the space between stimulus and response
Why the moment before action matters, and what becomes possible when it is held.
Frankl, V. E. (1946). Man's Search for Meaning.
Frankl's account of meaning-making under conditions of extreme constraint includes the phrase that anchors Chapter 1's reframing of fight, flight, and freeze: "Between stimulus and response there is a space. In that space is our power to choose our response. In our response lies our growth and our freedom." The Perry Approach treats that space as the place where the cloud method does its work — the freeze held long enough for integration to become possible. Referenced in Chapter 1.
The self held lightly — negation and the "as not"
Why releasing a fixed self-image is the ground of lasting change.
Paul of Tarsus (c. 54 CE). First Letter to the Corinthians, 7:29–31.
The source of the phrase hos me — "as not": to have as though not having, to live within one's circumstances without being closed or defined by them. The Perry Approach reads the NOT in D as a practical form of this posture — holding the current self as not final, so that something genuinely new can arrive. Referenced in Chapter 5.
Agamben, G. (2005). The Time That Remains: A Commentary on the Letter to the Romans (trans. P. Dailey). Stanford University Press.
Agamben's reading of Paul places the hos me at its centre — neither renunciation nor possession, but a third stance that holds every identity and role as revocable. The philosophical grounding for treating negation as an open posture rather than a swap of one fixed position for another. Referenced in Chapter 5.
Adaptive change and adult development
Why some change requires more than new techniques.
Kegan, R., & Lahey, L. L. (2001). How the Way We Talk Can Change the Way We Work: Seven Languages for Transformation. Jossey-Bass.
The book in which Karl first recognised the structure of the Evaporating Cloud inside the 'Immunity to Change' map — competing commitments as the cloud's B and C needs, and Big Assumptions as the beliefs holding the conflict in place. Referenced in Chapters 2 and 4.
Kegan, R., & Lahey, L. L. (2009). Immunity to Change: How to Overcome It and Unlock the Potential in Yourself and Your Organization. Harvard Business Press.
The fuller articulation of the Immunity to Change method, including the practice of surfacing and testing Big Assumptions. This developmental mechanism — why understanding alone doesn't move us — is the adaptive layer of the Perry Approach. See also Kegan's talk An Evening with Robert Kegan and Immunity to Change (2012), a live exploration of the same ideas. Referenced in Chapters 2 and 12.
Cognitive frameworks
The patterns underneath how we think.
Kahneman, D. (2011). Thinking, Fast and Slow.
Kahneman's synthesis of decades of collaborative research with Amos Tversky on the two modes of human thinking. System 1 is fast, automatic, pattern-matching, and low-cost. System 2 is slow, deliberate, integrative, and expensive. The book is dedicated to Tversky, who died in 1996, before its publication. The Perry Approach treats the Evaporating Cloud as a System 2 method that, with practice, becomes a bridge into a trained System 1 — second nature, or unconscious competence. Referenced in Chapter 1.
Lafferty, J. C., & Cooke, R. A. — the Life Styles Inventory (LSI) and the Human Synergistics Circumplex.
Clayton Lafferty and Robert A. Cooke developed the Circumplex, a measurement framework that arranges twelve thinking styles around a circle in two broad families — constructive (achievement, self-actualising, humanistic, affiliative) and defensive (security- and approval-driven). It gives the Perry Approach an empirical map of the security–satisfaction tension and the direction transformation has to take: from defensive towards constructive. The same Circumplex framework underlies the Group Styles Inventory (team-level) and the Organisational Culture Inventory (organisation-level), giving the Perry Approach a single measurement family that runs from the individual through the team to the whole organisation. Referenced in Chapters 1 and 2.
Cooke, R. A., & Lafferty, J. C. — the Group Styles Inventory (GSI).
The team-level instrument in the Human Synergistics Circumplex family. Where the LSI measures an individual's thinking and behaviour patterns and the OCI measures organisational culture, the GSI measures how a group actually interacts while it is working together — surfacing the constructive, passive-defensive, and aggressive-defensive patterns that shape team performance. Used in the Perry Approach to make team behaviour as observable and measurable as individual style and organisational culture, and to track the shift as a team's working assumptions change. Referenced in Chapter 1.
Cooke, R. A., & Szumal, J. L. (2000). Using the Organizational Culture Inventory to understand the operating cultures of organizations. In N. M. Ashkanasy, C. P. M. Wilderom, & M. F. Peterson (Eds.), Handbook of Organizational Culture and Climate. Sage.
The research underpinning the circumplex measurement of constructive and defensive styles at the level of organisational culture.
Vulnerability, courage, and daring leadership
A later influence — the security–satisfaction tension in the language of leadership.
Brown, B. (2018). Dare to Lead: Brave Work. Tough Conversations. Whole Hearts. Random House.
Brené Brown's research into vulnerability, shame, and courage, distilled into a leadership framework of armoured versus daring leadership. Her armour — control, perfectionism, self-protection — is the security end of the Human Synergistics Circumplex in plain language; daring is the willingness to move towards the constructive. Brown arrived long after the Perry Approach had taken shape, so she is not one of its foundations — but her vocabulary became part of how Karl teaches the security–satisfaction tension, especially with leaders. See also her talk The Power of Vulnerability (TEDxHouston, 2010). Referenced in Chapters 2 and 7.
This list is partial and will grow as the book grows. If you spot a source that should be here, get in touch.