The Operating Field Guide
How an agent keys the transmitter and goes back to receive as soon as an over ends. How it runs a contest QSO from CQ to logged contact, and how it handles the problems that come up on a real band. Every rule in it has been tested on the air.
The serial-console Field Guide
The console model, connection settings, the console standard, the device playbook, Junos and IOS basics, and worked sessions from a real EX2200 console.
The wsjtx-mcp guide
At a glance, installing, the first session, how the UDP model works, the transmit gate, the tools, running alongside other UDP consumers, and the remote host.
The API references for fldigi XML-RPC, N3FJP TCP and the WSJT-X UDP protocol are linked from each product's Documents section and from Downloads.