Concise and complete. I think the title is asking too much 
By "concise but complete" I mean just enough details to understand how consensus is established and maintained [and not so much that the important points are obscured]. An example of what I'm looking for, applied to bitcoin, would be:
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How are new blocks added to the blockchain?
Nodes assemble recent transactions into a block and attempt to find a nonce that when hashed with the new blockheader (which is cryptographically linked to the previous blockheader) produce a number less than some target:
hash(blockheader, nonce) < target.
If a node finds such a nonce, it publishes the solution to the network. Other nodes signal their acceptance of this new block by attempting to build new blocks on top of it.
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After leaving the network for some length of time, how does a node determine the current state of the blockchain?
Upon rejoing the network, a node considers valid chains where:
(1) the blockheaders form a cryptographic chain linking back to Bitcoin's genesis block,
(2) all transactions are permitted according to the protocol rules,
and selects the valid chain with the greatest cumulative work.
Cumulative work is
cumulative work = work in block 0 + work in block 1 + … + work in block n-1 + work in block n,
where n is the number of blocks in the chain, and the work in the ith block is
worki = fcn(hash(blockheaderi, noncei)).
