I don’t know what the best book would be, but I found this extract from Andy Farnell’s book “Designing Sound” to be a very helpful introduction to Pure Data:

http://aspress.co.uk/ds/pdf/pd_intro.pdf

Another useful book is “Loadbang - ProgrammingElectronic Music in Pd” by Johannes Kreidler. The 2nd edition is evidently out of print, but a free download is available here:

https://www.wolke-verlag.de/musikbuecher/johannes-kreidler-l...