A thermal control system (20;100) for directly or indirectly controlling temperature of at least one reaction vessel in which chemical and/or biochemical reactions may take place and/or the contents thereof, the temperature being controlled between at least a highest predetermined temperature and a lowest predetermined temperature, the system comprising: a thermal mount (21;101) for receiving the reaction vessel(s), one or more thermal sensors for sensing the temperature of one or more of the thermal mount, the reaction vessel(s) and/or the contents thereof, a heating liquid path (30;H1;H2) having a liquid therein, the heating liquid path extending between the thermal mount and a heating element (31;37;50) for heating the liquid to a temperature at least as high as the highest predetermined temperature, a cooling liquid path (28;C1;C2) having a liquid therein, the cooling liquid path extending between the thermal mount and a cooling element (29;36;49) for cooling the liquid to a temperature at least as low as the lowest predetermined temperature, means for causing the liquids in the heating and cooling liquid paths to move between the thermal mount and the respective heating and cooling elements, and a controller coupled to the thermal sensor(s) for controlling movement of the liquids in the heating and cooling liquid paths to and from the thermal mount and the respective heating and cooling elements in accordance with the sensed temperature(s) so that the temperature of the reaction vessel(s) and/or its contents reaches or is maintained at a desired temperature for a desired amount of time, characterised in that the thermal mount comprises thermally conductive material, wherein the heating liquid path (30;H1;H2) and the cooling liquid path (28;C1;C2) are separate paths through or adjacent at least part of the thermal mount, and wherein the heating liquid path (30;H1;H2) comprises a closed liquid path arranged to pass through or adjacent the heating element (31;37;50) so that the liquid therein is heated to a temperature at least as high as the highest predetermined temperature and to pass through or adjacent the thermal mount (21;101) so that the heating liquid is used to heat the thermal mount, and thereby to cool down as it passes through or adjacent the thermal mount and the cooling liquid path (28;C1;C2) comprises a closed liquid path arranged to pass through or adjacent the cooling element (29;36;49) so that the liquid therein is cooled to a temperature at least as low as the lowest predetermined temperature and to pass through or adjacent the thermal mount so that the cooling liquid is used to cool the thermal mount, and thereby to heat up as it passes through or adjacent the thermal mount. a thermal mount (21;101) for receiving the reaction vessel(s), one or more thermal sensors for sensing the temperature of one or more of the thermal mount, the reaction vessel(s) and/or the contents thereof, a heating liquid path (30;H1;H2) having a liquid therein, the heating liquid path extending between the thermal mount and a heating element (31;37;50) for heating the liquid to a temperature at least as high as the highest predetermined temperature, a cooling liquid path (28;C1;C2) having a liquid therein, the cooling liquid path extending between the thermal mount and a cooling element (29;36;49) for cooling the liquid to a temperature at least as low as the lowest predetermined temperature, means for causing the liquids in the heating and cooling liquid paths to move between the thermal mount and the respective heating and cooling elements, and a controller coupled to the thermal sensor(s) for controlling movement of the liquids in the heating and cooling liquid paths to and from the thermal mount and the respective heating and cooling elements in accordance with the sensed temperature(s) so that the temperature of the reaction vessel(s) and/or its contents reaches or is maintained at a desired temperature for a desired amount of time, characterised in that the thermal mount comprises thermally conductive material, wherein the heating liquid path (30;H1;H2) and the cooling liquid path (28;C1;C2) are separate paths through or adjacent at least part of the thermal mount, and wherein the heating liquid path (30;H1;H2) comprises a closed liquid path arranged to pass through or adjacent the heating element (31;37;50) so that the liquid therein is heated to a temperature at least as high as the highest predetermined temperature and to pass through or adjacent the thermal mount (21;101) so that the heating liquid is used to heat the thermal mount, and thereby to cool down as it passes through or adjacent the thermal mount and the cooling liquid path (28;C1;C2) comprises a closed liquid path arranged to pass through or adjacent the cooling element (29;36;49) so that the liquid therein is cooled to a temperature at least as low as the lowest predetermined temperature and to pass through or adjacent the thermal mount so that the cooling liquid is used to cool the thermal mount, and thereby to heat up as it passes through or adjacent the thermal mount.