Richard Ogorkiewicz's new and rather excellent book, 100 years: evolution of the tank, is currently going dirt cheap (99p) on UK Amazon as a Kindle book.
Sorry, I don't know the situation in North America or Europe, you will need to check your local Amazon.
Since I have a new interview with Ken Estes available on my site, I thought I would start a thread on the topic. This is the place to post links to interviews with tankers and/or authors.
Marines Under Armor: An Interview with Kenneth Estes
Here are my older pieces:
A Military, Political and Global History of Armoured Warfare: An Interview with Alaric Searle
Patton versus the Panzers: An Interview with Steven Zaloga
Tank Warfare on the Eastern Front: An Interview with Robert Forczyk
Germany’s Panzer Arm in WWII: An Interview with R. L. DiNardo
Q & A with Jim Warford about Soviet/Russian Armor
Interview with Harry Yeide – Part 1: US Armor in World War II
Interview with Harry Yeide – Part 2: Fighting Patton
Interview with Steven Zaloga