Behind the Cloud – Enhancing Logical Thinking

(2011, 2014)

Jelena Fedurko

The book is about discovering the meaning behind the statements and logical connections in the Cloud – the central logical tool of TOC.

Behind the Cloud covers all aspects of writing a proper, sound and well-structured cloud which is a prerequisite for good understanding of problems and finding or constructing better solutions.

The book is written as a “study” and reference book. It brings deeper understanding of all elements of the cloud and detailed instructions for the entire process.

Forward to Behind the Cloud by Dr. Alan Leader

Every so often a book comes along that fills a gap, that makes us say, “That’s just what I was looking for.” Many of us in the TOC community consider the cloud to be our most powerful and most frequently used TP tool. We users will appreciate the careful attention Jelena Fedurko has given to our favorite construct, the cloud. Her knowledge of this tool, and her understanding of the logic behind it, are clearly expressed in these pages. The ample examples and detailed explanations make this unquestionably the most powerful book on clouds yet written. She has upgraded all of our knowledge, and provided a permanent addition to the TOC body of knowledge. We are all in her debt. If you are serious about TOC, you must own this book.

What readers say about Jelena’s books:

Your book [Behind the Cloud] has been a perfect support for me to dig further into the Cloud’s mechanisms, and its relationship with the other TP tools.

I’m quite a TOC newcomer, but already a big fan. I’m getting into Clouds and I heard very good feebdacks about your book.

I have read your book Behind The Cloud and enjoyed it very much. I learned many new ideas.  Thank you.

We recently acquired the book “Behind the Cloud” by Jelena Fedurko. An excellent guide to raising assumptions in a cloud!

I am one of the guys that I watched your presentation back in Germany about the UDE clouds and I also bought your new book [Through Clouds to Solutions]. I just wanted you to know that I found your book to be just great !!! you did an excellent job setting it up for all the rest of us. I found it extremely useful – I have read it 10 times and I advise it all the time. It is really excellent !!

I just wanted to thank you for your well written book [Mistakes and Difficulties in Working with TOC Logical Tools]. This is a great read for anyone wanting to REALLY understand clouds and CRTs.

Your previous books have been so good, I look forward to receiving your S&T Book.

All of your books are excellent.  Clean, clear, quick, no-nonsense teaching material.

I have begun using “Through Clouds To Solutions” to properly frame UDEs (reference 10 Rules) – & intend using it extensively to make the UDE clouds and then onwards to the core conflict & CRT, using the Three Cloud Method. This is to acknowledge that your work has been a ‘big big help’ – difficult to imagine how I would have managed it without your explanations,  error examples & workbook exercises… I feel sorry for the many TOC practitioners who are wanting to master the use of  cloud technique but are either unaware or not fully connected to your work, for whatever reasons – pity that they are not benefiting from your immense contribution in this area…..!!

Your book [Mistakes and Difficulties in Working with TOC Logical Tools] arrived last night it is fantastic!!! I have not stopped reading it.

Behind the Cloud – Table of Contents

  • Editor’s Forward by Alan H. Leader
  • From the author
  • Chapter 1: Why we work with clouds
  • Chapter 2: Process of learning the cloud
  • Chapter 3: People speak Clouds
  • Chapter 4: Typical mistakes in surfacing assumptions
  • Chapter 5: Four Assumption Rules for straight arrows A-B, A-C, B-D, C-D’
  • Chapter 6: Are these assumptions valid? Working with examples
  • Chapter 7: Case “Production planning”
  • Chapter 8: Case Part 1. Checking assumptions for arrow B-D. Assignment
  • Chapter 9: Case Part 1. Checking assumptions for arrow B-D. Answer
  • Chapter 10: Using Four Assumption Rules to build assumptions
  • Chapter 11: Case Part 2: Suggesting your assumptions for arrow B-D. Assignment
  • Chapter 12: Case Part 2: Suggesting your assumptions for arrow B-D. Answer
  • Chapter 13: Case Part 3. Checking assumptions for arrow C-D’. Assignment
  • Chapter 14: Case Part 3. Checking assumptions for arrow C-D’. Answer
  • Chapter 15: Case Part 4: Suggesting your assumptions for arrow C-D’. Assignment
  • Chapter 16: Case Part 4: Suggesting your assumptions for arrow C-D’. Answer
  • Chapter 17: Surfacing assumptions for arrow D-D’. Two D-D’ Rules
  • Chapter 18: Developing valid assumptions for arrow D-D’. Using D-D’ Rule “What is missing?”
  • Chapter 19: A brief recap on typical mistakes and 4+2 Assumption Rules
  • Chapter 20: Logical cross-check: “D endangers C”, “D’ endangers B”
  • Chapter 21: More about clouds
  • Chapter 22: Challenging assumptions
  • Chapter 23: Assumptions that we are not willing to challenge and assumptions that we are not aware of
  • Chapter 24: Injections
  • Chapter 25: Checking for negative side effects
  • Conclusion
  • Afterword by Oded Cohen

Behind the Cloud is 300 pages, soft covers.

To get information about the book and to purchase a hard copy – please contact

The second edition, revised and expanded, can be bought as an eBook at

Jelena is a TOC Expert in tocExpert, International Director of TOC Strategic Solutions, and a co-founder and co-president of TOCPA – the Theory of Constraints Practitioners Alliance.  She has worked with companies in the areas of production, project management, supply chain, distribution, and retail in more than 15 countries helping with TOC implementations.

Other books by Jelena Fedurko:

Behind the Cloud – Enhancing logical thinking (2011)

Through Clouds to Solutions – Working with UDEs and UDE Clouds (2013)

Mistakes and Difficulties in Working with TOC Logical Tools (2014)

A Good Strategy and Tactic Tree – Rules, Examples, Typical mistakes, Exercises with Answers (2016)


This combination of material will enable you to build good enough clouds and equip you with good understanding and practical tips how to work with assumptions and develop injections.

If you want to have further understanding of different types of Clouds and build solid knowledge on how to develop UDEs and how to work with UDE Clouds:

To get solid understanding of how to work with the Strategy and Tactic Tree: