Active, micro-well thermal control subsystem

A method of providing active thermal control of at least one of a sample-holding device and a reagent-containing device, the method comprising:

• coupling the sample-holding device and the reagent-containing device to a fluidic circuit;
• circulating a heat-transferring fluid for heating and/or cooling through the fluidic circuit;
• thermally-coupling a first assembly, including a controllable thermo-electric device and a heat removal device, to a first side of said sample-holding device;
• thermally-coupling a second assembly, including a controllable thermo-electric device, a heat removal device, and a heat spreader, to a second, opposing side of said sample-holding device;
• removing heat from the heat-transferring fluid in the fluidic circuit using at least one of said heat removal devices;
• and
• controlling the thermo-electric devices associated with the first and second assemblies to remove heat from or add heat to said sample-holding device.