I do remember when the "Mankind's Search for God" book was published and that it was intended to be used also in FS when meeting people from nonchristian denominations. I wonder what they may have thought: First, there is a very selective discussion of a religion and then it is announced by the WT with all its 'authority' why it is wrong. I have known some hindus and buddhists and can say the so-called information in it does not correspond to what they think is essential. The emphasis is on what the WT thinks is easy for the publishers to handle with their assumed bible understanding.
In fact, that book is just another attempt of the JW organization to invalidate other false religions. Just a couple of excerpts from the yellow bound book "What Has Religion Done for Mankind?" (1951), have some serious fun:
In the chapter Buddhism, a Salvation by Psychology, their concluding statement is: "In this day when human psychology proves itself unable to scheme out any salvation for men, it is time for buddhists and all others to turn to Jehovah God for true enlightment." (p.213)
The next chapter on Confucianism contains the following pearl, exemplifying the amazing logic a la WT: "Confucianism is not the real science of government, for it has no prophetic vision of the great theocratic government of Jehovah God." (p.224)