Part I Preliminaries in a Nutshell 1 Gravitation． 1．1 The Curved Spacetime 1．2 The Curved Spacetime：an Example 1．3 TheEitein Equation 2 Matter Components 2. 1 The StressTeor 2．2 Perfect Fluid 2. 3 Observe and Energy Conditio 2．4 TheVacuum 2．5 Particles． 2．6 Homogeneous Field Configuratio 3 Cosmology 3．1 The Cosmological Principle 3．2 Newtonian Cosmology 3．3 FRW Cosmology Part II Theoretical Aspects 4 Introduction to Dark Energy 4．1 The Cosmological Cotant Reloaded 4．2 TheTheoretical ChallengeReferences 5 Weinberg's Classification 5.1 Supeymmetry 5.2 Anthropic Principle 5.3 Tuning Mechanism 5.4 Modifying Gravity 5.5 Quantum Cosmology References 6 Symmetry 6.1 Supeymmetry in 2{1 Dimeio 6.2 t HooftNobhenhuis Symmetry 6.3 KaplanSundrum Symmetry 6.4 Symmetry of Reveing Sign of the Metric 6.5 Sealing Invariance in D > 4 References 7 Anthropic Principle 7.1 BoussoPolchiki Scenario 7.2 KKLT Scenario 7.3 Populating the Landscape and Anthropic Interpretatio. References 8 Tuning Mechanisms 8.1 Brane veus Bulk Mechanism 8.2 Black Hole SelfAdjustment References 9 Modified Gravity 9.1 f(R) Models 9.2 MOND and TeVeS Theories 9.3 DGP Model 9.4 Other Modified Gravity Theories References 10 Quantum Cosmology 10.1 Cosmological Cotant Seesaw 10.2 Wave Function through the Landscape References 11 Holographic Principle 11.1 The Holographic Principle 11.2 Holographic Dark Energy 11.3 Complementary Motivatio 11.4 Agegraphic Dark Energy 11.5 Ricci Dark Energy References 12 BackReaction 12.1 SubHubble Inhomogeneities 12.2 SuperHubble Inhomogeneities References 13 Phenomenological Models 13.1 Quintessence, Phantom and Quintom 13.2 KEssee, Custuton, Braiding and Ghost Condeation 13.3 Higher Spin Fields 13.4 Chaplygin Gas and Viscous Fluid 13.5 Particle Physics Models 13.6 Dark Energy Perturbatio References 14 The Theoretical Challenge Revisited References Part III Observational Aspects 15 Basis of Statistics 15.1 X2 Analysis 15.2 Algorithms for the BestFit Analysis 15.3 The Markov Chain Monte Carlo Algorithm 15.4 The Fisher Matrix Techniques References 16 Cosmic Probes of Dark Energy 16.1 Type Ia Supernovae 16.2 Cosmic Microwave Background 16.3 Baryon Acoustic Oscillatio 16.4 Weak Leing 16.5 Galaxy Cluste 16.6 GammaPay But 16.7 XRay Observatio 16.8 Hubble Parameter Measurements 16.9 Cosmic Age Tests 16.10 Growth Factor 16.11 Other Cosmological Probes References 17 Dark Energy Projects 17.1 OnGoing Projects 17.2 IntermediateScale, NearFuture Projects 17.3 LargerScale, LongerTerm Future Projects References 18 Observational Cotraints on Specific Theoretical Models 18.1 Scalar Field Models 18.2 Chaplygin Gas Models 18.3 Holographic Dark Energy Models 18.4 DvaliGabadadzePorrati Model 18.5 f(R) Models 18.6 Other Modified Gravity Models 18.7 Inhomogeneous LTB and BackReartion Models 18.8 Comparison of Dark Energy Models References 19 Dark Energy Recotructio from Observational Data 19.1 Specific Aatz 19.2 Binned Parametrization 19.3 Polynomial Fitting 19.4 Gaussian Process Modeling References Index