This book gives an accessible overview of the role and potential of mathematical optimization in call centers. It deals extensively with all aspects of workforce management, but also with topics such as call routing and the scheduling of multiple channels. It does so without going into the mathematics, but by focusing on understanding its consequences. This way the reader will get familiar with workload forecasting, the Erlang formulas, simulation, and so forth, and learn how to improve call center performance using it. The book is primarily meant for call center professionals involved in planning and business analytics, but also call center managers and researchers will find it useful. There is an accompanying website which contains several online calculators.
It's such a useful book if you're looking for a way to confirm your own self-learning.
Still the book is not written in an easy way. Examples are confusing and sometimes refer to figures which are two pages ahead or before. It requires careful re-reading to understand the concepts clearly and even then it's still a bit difficult.
It is my understanding though that more and more we have a new medium of communication between companies and people which is a middle ground between email and live chat. Imagine Whatsapp in which you send a message and are waiting for an answer soon but not at the moment.
While we can apply many of the concepts learned in the book and general operations management research on calls and emails I feel there is lack of literature for this specific channel.