There is a good Australian book by Aviation Theory Centre (ATC) called "Avionics & Flight Management Systems for the Air Transport Pilot"
It includes INS / IRS, EFIS, FMS, Autopilot and Flight Director systems, Warning systems (GPWS and TCAS) and Recording systems (flight data and voice recorders)
Check out
www.flyingbooks.com.au or
www.aviationtheory.net.au or
www.pilotshopwa.com.au
Let me know if you have a problem getting the book