To summarize this network, zcash is the bitcoin whose transactions are secret. Of course, in the Bitcoin network, the sender's details are not known, but the amount transferred and the wallet balance are known.
In my opinion, there was no need to present this network, because in 2014, two years before the introduction of this network, dash was introduced, which has almost the same features as zec. Of course, dash was a blockchain with bitcoin code, but it was not a fork.