Important alert: People should be aware that this is yet another Chabad scam.
The book/let is from Chabad. However, to obscure that, and fool unknowing readers, the poster writes “I have come across a sefer I bought in Lakewood”. Some people, seeing the word Lakewood, might assume that it is Litvish-Yeshivish (even though there are many Chasidim in Lakewood today). But it is not from such an author.
“He deservedly received haskamos from several Rebonim including Rabbi Zev Leff Shli’ta.”
Sometimes Lubavitchers approaches general rabbonim that are not schooled in their wiles and deceptive tactics, and try to meet with them and get endorsements from them. And sometimes the targets may even fall for it, especially after Chabad flatters them. But don’t be fooled. They are just using them for their nefarious propaganda purposes.