1 Temperature in Biological Species<br>1.1 Temperature in Our Life<br>1.2 Body Temperature<br>1.3 Effects of Environmental Temperature on Biological Function<br>1.4 Molecules Associated with Biological Responses to Environmental Temperature<br> <br>2 Development of Fluorescent Molecular Thermometers<br>2.1 Physical Chemistry of Fluorescence<br>2.2 Fluorescent Molecular Thermometers<br>2.2.1 Small Organic compounds involving intersystem crossing<br>2.2.2 Small Organic Compounds Involving Conformational Change<br>2.2.2 Organometallic Complexes<br>2.2.3 Excimers and Exciplex<br>2.2.4 Host-Guest Complexes<br>2.2.5 Thermoresponsive Macromolecules<br>2.2.6 Inorganic Materials<br>2.2.7 Others<br> <br>3 Intracellular Thermometry with Fluorescent Molecular Thermometers<br>3.1 Early Attempts for Cellular Thermometry <br>3.2 Introduction of Fluorescent Molecular Thermometers into a Living Cell <br>3.3 Cytotoxicity Assessment<br>3.4 Practice of Intracellular Thermometry with Fluorescent Molecular Thermometers<br>3.5 Intracellular Thermometry with Organelle-targeted Fluorescent Molecular Thermometers<br>3.6 Intracellular Thermometry of Brown Adipocytes<br>3.7 Application of Intracellular Thermometry in Various Biological Fields<br> <br>4 Cellular Thermometry Based on Non-fluorometric Principles<br>4.1 Infrared Thermometry <br>4.2 Photoacoustic Thermometry <br>4.3 Raman Thermometry <br>4.4 Use of Transmission Spectroscopy <br>4.5 Thermocouples<br>4.6 Resonant Thermal Sensors<br>4.7 Bimaterial Microcantilevers<br>4.8 Thermistors<br> <br>5 Reliability of Intracellular Thermometry with Fluorescent Molecular Thermometers<br>5.1 Validity of a Calibration Curve <br>5.2 Possible Artifacts in Thermometry of Biological Samples<br>5.3 Difference between Experimentally Observed and Theoretically Calculated Intracellular Temperature Variation<br> <br>6 The Future of Intracellular Thermometry<br>6.1 In vivo Thermometry<br>6.2 Thermal Medicine<br>6.3 Thermal Signaling<br>6.4 Absolute Determination of Intracellular Temperature<br>6.5 Simultaneous Measurement of Multiple Parameters<br>6.6 Intracellular Thermometry of Plant Cells<br> <br>Appendix<br>A.1 Review and account items on fluorescent molecular thermometers<br>A.2 Comprehensive collection of fluorescent polymeric thermometers based on the combination of a thermoresponsive polymer and an environment-sensitive fluorophore<br>A.3 Comprehensive collection of fluorescent nanogel thermometers based on the combination of a thermoresponsive polymer and an environment-sensitive fluorophore<br>A.4 Non-covalent mixtures of a thermoresponsive polymer and an environment-sensitive fluorophore<br>A.5 Fluorescent logic gates based on the combination of a thermoresponsive polymer and an environment-sensitive fluorophore<br>A.6 Fluorescent inorganic thermometers<br>