Deep Work by Cal Newport is a book I recommend to all my students. In the recent 30 Day Intensive reading the book and working it through was one of the tasks.
I read this book several years ago for the first time and it is with me ever since. I am quite certain it is the most important non-fiction, non-philosophy book I have read in many years.
I adopted many ideas from the book and felt also very confirmed in things that I do a bit differently from what is expected nowadays (like not checking my E-Mail account every five minutes), but hurting the brain and concentration.
Read the book and then stop freaking out when someone is not answering your E-Mail within 5 minutes. „Spend enough time in a state of frenetic shallowness and you permanently reduce your capacity to perform deep work.”