
This book provides a systematic introduction to functions of one complex variable. Its novel feature is the consistent use of special color representations – so-called phase portraits – which visualize functions as images on their domains. Reading Visual Complex Functions requires no prerequisites except some basic knowledge of real calculus and plane geometry. The text is self-contained and covers all the main topics usually treated in a first course on complex analysis. With separate chapters on various construction principles, conformal mappings and Riemann surfaces it goes somewhat beyond a standard programme and leads the reader to more advanced themes. In a second storyline, running parallel to the course outlined above, one learns how properties of complex functions are reflected in and can be read off from phase portraits. The book contains more than 200 of these pictorial representations which endow individual faces to analytic functions. Phase portraits enhance the intuitive understanding of concepts in complex analysis and are expected to be useful tools for anybody working with special functions – even experienced researchers may be inspired by the pictures to new and challenging questions. Visual Complex Functions may also serve as a companion to other texts or as a reference work for advanced readers who wish to know more about phase portraits.
It includes 12 visualizations of selected complex functions and their background and related mathematicians. I would highly recommend reading them. Prof. Dr. Elias Wegert, the author who actively contributes to this calendar, also wrote Visual Complex Functions: An Introduction with Phase Portraits which is mentioned by another comment here.
[1]: https://blogs.hrz.tu-freiberg.de/mathekalender/english/
Edit: Navigate to the german page if you want to buy it
Check this out:
https://www.amazon.com/Visual-Complex-Functions-Introduction...
Personally I don’t think it’s ideal to use as an only book for a complex analysis course, but I found it very helpful for crystalizing my intuition/thinking about the subject. I would recommend every university math student try reading it, especially after going through a traditional course. (Also recommended is Wegert’s book Visual Complex Functions, but definitely not as a primary text.)
Finally, I suspect switching primary books is only going to work well if the professor makes a commitment to teaching using the same explanations. If the book goes about the subject in a completely different way than the lectures, I can well imagine students working homework sets on a short deadline may get confused.
Prof. Elias Wegert, the author who actively contributes to these calendars, also wrote Visual Complex Functions: An Introduction with Phase Portraits[1].
Sarason's book is only 160 pages long, with legible text and clear examples. It covers the length of an undergraduate university class, and explains Holomorphic functions perfectly. The proofs are crystal clear, and so are the motivations. I haven't seen a better introduction.