Abstract: The nature of the normal state and the origin of the high-TCsuperconductor (HTSC) in the cuprates is still a major unsolved problem. The thermopowerS of the cuprate superconductor La2−xCexCuO4 (LCCO)thin films was measured in magnetic fields large enough to access the normalstate at low temperatures, for a range of Ce concentrations from x = 0.11 to x= 0.16. The thermopower in the cupratesuperconductor LCCO suggests that its Fermi surface undergoes a reconstruction forx ≤ 0.14. For 0.15 and 0.16 samplesS/T varies with lnT at low temperature. This analysis indicatesthat low-T thermopower may be influenced by spin fluctuations which areimportant for the superconducting mechanism.