Imho the best book on hobby cnc is this forum.
For the tolerances you require I think you will need to spend the money on a professional machine.

So what is your situation exactly, what hardware do you already possess? A 200w laser head? What type of laser?

The connection types of a CNC.... hmmm ..... I guess you are talking about proprietary connectors like those in HAAS machines, if so then the only the manufacturer documentation will shed light on it.

As for the 98% of hobby cnc machines there is only one connector, the parallel port. Usually hobby laser cnc uses a pwm to control laser output, perhaps the laser head you have needs a proprietary controller.

As for general idea about cnc is this:
the gcode is sent over the parallel port in 2 pulses for the axis, a direction and a step, the motor drive will move the motor one step in the direction specified. There are some standalone controllers made with micro-controllers like Arduino but it is not widespread yet.

So for a simple cnc you need:
a.- motor drive (servo or stepper)
b.- motor (servo+encoder or stepper motor)
c.- break out board (connects the drive to lpt)
d.- some linear motion components (linear bearings and belts/screws)
Mix the above to meet your needs (amount of axises, table size, tolerances, etc)
e.- software to execute gcode (Mach, Turbocnc, EMC, etc)