Thank you all for your input , I deeply appreciate it.
I am mostly interested in this specific book because I am planning on buying it but since it is quite expensive, I would like to hear some opinions first about it. If you have any other related book recommendations , please let me know.
So far I have enjoyed reading
Music Synthesizers - A Manual Of Design & Construction By Delton T.Horn
Also by the same author, I have also enjoyed
Oscillators simplified with 61 projects, although it is not synthesizer specific.
By the way does anybody know who Delton T.Horn was and if he played a role in the synthesizer industry?