Mates,
Thanks in advance for all your kind supports.
Due to the fact that my book is dedicated to V. 2x, I decided to reduce the proposed price to $6 and think for those who may find it handy, it is the right time to buy it. The basics concepts on material and lighting in the most recent version are the same as previous( I mean the main concepts such as Reflection, refraction, bump, displacement, light values, light types, etc) and even in some realms, the changes are very subtle. But the interface has drastically changed so if one is going to use the recent versions, my book is outdated and obsolete.
I hope to have some spare time to update it to the most recent version if my computer bears it (while seems due to rapid updates, it is not so wise).
Just saw that a most recent and comprehensive book for more advanced users is announced on the sub-forum by another user.