Soft matter consists of mesoscopic objects such as colloidal particles, polymer chains, or macromolecules, which are often suspended in a liquid medium, often with addional ions. Traditional examples of such systems are blood, mud, hairgel, yoghurt, or paint, but more recent examples include liquid crystals, photonic bandgap materials, DNA in the living cell, and e-ink.The traditional picture of these systems a "dirty chemical soup" is no longer true due to spectacular advances in chemical synthesis and microscopy, resulting in clean and well-defined model systems that can be studied in great detail experimentally. In this course we will discuss the phenomenology of this systems from a theoretical perspective, with a focus on e.g. phase transitions, structure, spontaneous ordering, medium-induced effective interactions, Brownian dynamics. We will develop the theory to interpret, describe and predict physical properties of these systems. A short initial crash-course on classical statistical mechanics (thermodynamic potentials, Legendre transforms, ensembles, partition functions, etc.) will be extended to describe interacting many-body systems (virial expansion, distribution functions, Ornstein-Zernike theory, thermodynamic perturbation theory, van der Waals theory, critical exponents, hard-sphere crystallisation, and density functional theory). Further extensions to describe ionic liquids and colloidal suspensions will be discussed (Debye-Hueckel theory, screening, Poisson-Boltzmann theory, DLVO theory, effective many-body interactions, depletion effect due added polymers, charge renormalization). Also liquid crystals (nematic, smectic, columnar phases, Onsager theory), polymers (random walks, theta collapse, flexibility, persistence length,scaling concepts), interfacial phenomena (adsorption, wetting, surface tension, capillary waves, density profiles, droplets), and (hydro-)dynamic effects (Brownian motion, Langevin equation, dynamic density functional theory) will be covered.