Single molecule biophysics and poisson process approach to statistical mechanics This is an overview of single molecule physics the study of both equilibrium and non equilibrium properties at the single molecule level. It begins with an introduction to this fascinating science and includes a chapter on how to build the most popular instrument for single molecule biophysics the total internal reflection fluorescence (TIRF) microscope. It concludes with the Poisson process approach to statistical mechanics explaining how to relate the process to diverse areas and see how data analysis and error bars are integral parts of science Appendices. A. Building a total internal reflection fluorescence microscope: parts vendors and costs B. The Poisson process Preface 1. Single molecule biophysics 1.1. Introduction 1.2. A brief history of single molecule study 1.3. Single molecule methods 1.4. Single molecule data analysis 1.5. Brief overview of thermodynamics and statistical mechanics 1.6. Future outlook 1.7. Conclusion 3. Poisson process approach to statistical mechanics 3.1. Introduction 3.2. Diffusion 3.3. Inter conversion of the states of molecules 3.4. Photon statistics from lasers 3.5. Statistics of fluorescent centers on a surface 3.6. Location of stars in the sky 3.7. Quantifying the heterogeneity of the locations of cosmic ray sources 3.8. Conclusion 3.9. Acknowledgments 2. The total internal reflection fluorescence microscope 2.1. Introduction 2.2. Design considerations 2.3. Microscope frame and associated parts 2.4. Microscope objectives 2.5. Detection path and camera 2.6. Excitation path 2.7. Computer computer software and other computing hardware 2.8. Experimental protocol for slide preparation 2.9. Specifications of the TIRF microscope 2.10. Objective type TIRFM 2.11. Multichannel detection and FRET 2.12. Circular dichroism spectroscopy and microscope enclosure 2.13. Acknowledgments