that I picked up myself for when I was at my last workplace:
http://www.amazon.com/Work-Find-Meaning-Each-Hour/dp/1937006204

although there are many this is obviously most directly relevant. His story is amazing too as a peace activist that MLK nominated for the Nobel Peace Prize. You might look up his talks on youtube where he is also verbally teaching one on how to apply Zen mindfulness/meditation via sitting, walking, or other activities. I consider his approach critical to me not going apeshit haha
The most basic way to put the sitting version of Zen meditation is being in some type of comfortable position and breathing very long and slow for whatever amount of time like 15-30 minutes, focusing completely only on the sensation of the air entering and leaving your chest and nose/mouth no matter what randomness tries to inevitably clutter your mind causing the stress. Mastery of this practice means it can be done almost anywhere and can create that peace on a regular basis in this moment that we are always chasing at some other time/place/method.