An apparatus for providing immersion cooling in a circuit card environment, the apparatus comprising: a circuit card including first and second longitudinally spaced circuit card subassemblies (204, 206), connected together into a single circuit card oriented substantially in a lateral-longitudinal plane, the first and second circuit card subassemblies (204, 206) being connected together by a laterally extending card connector (210, 321) oriented in a parallel lateral-longitudinal plane to the first and second circuit card subassemblies (204, 206), the first and second circuit card subassemblies (204, 206) having first and second operating temperatures, respectively, the first and second operating temperatures being different from one another; and a thermal energy transfer device (114, 116) operatively connected to an area of the circuit card correlated with a selected one of the first and second circuit card subassemblies (204, 206), the thermal energy transfer device (114, 116) being a circulating-coolant heat sink, the thermal energy transfer device (114, 116) at least partially inducing the respective one of the first and second operating temperatures to the selected circuit card subassembly (204, 206), the thermal energy transfer device (114, 116) transversely overlying at least a supermajority of the selected circuit card subassembly (204, 206) and being laterally spaced from the other circuit card subassembly (204, 206), wherein the thermal energy transfer device (114, 116) is a first thermal energy transfer device, and including a second thermal energy transfer device operatively connected to an area of the circuit card correlated with the other one of the first and second circuit card subassemblies (204, 206), the second thermal energy transfer device at least partially inducing the respective one of the first and second operating temperatures to the other circuit card subassembly (204, 206), the second thermal energy transfer device transversely overlying at least a supermajority of the other circuit card subassembly (204, 206) and being laterally spaced from the selected circuit card subassembly (204, 206), wherein one of the first and second operating temperatures is in the range of about 2-6K, and more specifically is about 4K, and the other of the first and second operating temperatures is in the range of about 75-79K, and more specifically is about 77K. a circuit card including first and second longitudinally spaced circuit card subassemblies (204, 206), connected together into a single circuit card oriented substantially in a lateral-longitudinal plane, the first and second circuit card subassemblies (204, 206) being connected together by a laterally extending card connector (210, 321) oriented in a parallel lateral-longitudinal plane to the first and second circuit card subassemblies (204, 206), the first and second circuit card subassemblies (204, 206) having first and second operating temperatures, respectively, the first and second operating temperatures being different from one another; and a thermal energy transfer device (114, 116) operatively connected to an area of the circuit card correlated with a selected one of the first and second circuit card subassemblies (204, 206), the thermal energy transfer device (114, 116) being a circulating-coolant heat sink, the thermal energy transfer device (114, 116) at least partially inducing the respective one of the first and second operating temperatures to the selected circuit card subassembly (204, 206), the thermal energy transfer device (114, 116) transversely overlying at least a supermajority of the selected circuit card subassembly (204, 206) and being laterally spaced from the other circuit card subassembly (204, 206), wherein the thermal energy transfer device (114, 116) is a first thermal energy transfer device, and including a second thermal energy transfer device operatively connected to an area of the circuit card correlated with the other one of the first and second circuit card subassemblies (204, 206), the second thermal energy transfer device at least partially inducing the respective one of the first and second operating temperatures to the other circuit card subassembly (204, 206), the second thermal energy transfer device transversely overlying at least a supermajority of the other circuit card subassembly (204, 206) and being laterally spaced from the selected circuit card subassembly (204, 206), wherein one of the first and second operating temperatures is in the range of about 2-6K, and more specifically is about 4K, and the other of the first and second operating temperatures is in the range of about 75-79K, and more specifically is about 77K.