A few quotes from course emails (suspect, as they are curated by the instructors:)

N. K.: “During last two years I have completed more than 20 online courses on different platforms and this is my favorite. Every week combination of reading, lectures and assignment clarified everything. Simply the best.” 

M. V.: “Thank you very much for all the work and effort and for organising such an incredible course. I finished more than 10 physics or physics-related courses on Coursera and EdX and this was my favourite so far!”

E. P.: “I'm really delighted with the way course is going (videos + interactive book + Python (have >4 yrs of Python usage experience) + auto-grading system) - it is really fresh and modern.”

G. B.: “It's been a fantastic experience to go through the course, and maybe now I start understanding what was meant by`you'll know something your professor doesn't know...’. I'm still amazed by the beauty and efficiency of the zeta functions and various applications of the trace formula. What's also interesting, I had known ChaosBook for more than 10 years... but I can now realize that on my own I had no clue of what was lying inside. These few months here have turned everything upside down thanks to the focus brought by the pace of lectures and the assignments - and I'm sure there's still plenty of hidden gems that I overlooked.”

M. R.: “I really enjoyed both courses, especially the part where we "learnt how to count" using the spectral determinant and the dynamical zeta function, which were totally new to me.”

N. R.: “Many thanks for an excellent course! It's fantastic to have such resources freely available while still getting the full offering that the campus students have.”

M. G.: “Thank you for the course and everything, I had a lot of fun and learned a lot! It's been a pleasure and a privilege. So long, and thanks for all the fishing tips. :)”

K. B.: “The course was very educational and provided a lot of insight into this subject as well as connections to many other classes I've taken on QM, statistical mech., and so on. I enjoyed the focus on group theory at the end because this subject tends to get glossed over and then everyone sort of assumes that you somehow just know it. And I did learn something that my professors don't know, so your promise was upheld! :)”

M. L.: “I would not have known about the course if my professor would not have mentioned it in a lecture. I prefer the blackboard-style videos but I used mainly the ChaosBook chapters.”

D. W.: “I really enjoyed it, I really learned things which I wished I would have learned 5 years earlier in my physics studies. This course really cleared up my mind. I will repeat part 2 when I find time again!”

D. L.: “Yesterday I started to derive the Langevin dispersion equation, and I found some of the things we did in class very useful to get through the math quicker. Very satisfying”

Y. E. G.: “I would like to thank you (and entire teaching team) for the great course. Study hard! Teach harder! I am not sure that I have deeply understood everything about chaos, but at least I feel confident with some things that I can calculate now!”

P. K. G.: “The course was an exhilarating experience. It has given me new insights, sleepless nights, hands on experience with the subject and great material to write about on my blog. Thank you for the ChaosBook.”

R. C.: “I would like to thank you for the opportunity you gave me to learn so advanced theoretical subjects. [...] your course was very funny because it was based both on Mathematics and Python programming. I'm sure both will be useful for me in the future. I will always remember the satisfaction I felt studying your matter and overcoming the homeworks. I hope to soon take up your ChaosBook to deepen many of the proposed topics. I really enjoyed myself, and now, at the end of all, I'm really satisfied to have attended both the courses.”

M.-H. C.: “Thank you and your team for making this great online course. It will be very honorable for me to receive the Statement of Accomplishment for this course. Hope this course can be presented on Coursera, edX or any other MOOCs platform without a hitch in the future and then let more people be able to join the class. Again, thank you and your team with my respect.”

Anonymous: “This course was 10^6 times harder than any other course on the internet.”