This course aims at introducing the techniques to value derivative products in an arbitrage-free way. We shall start with the celebrated Black-Scholes model. We shall recall the binomial tree setup and then proced with the continuous time setup. We shall then review the fundamental theorems of asset pricing. Equipped with these fundamental tools, we will focus on specific products. The course will be enriched with the participation of speakers from the private sector active in the field. They will discuss these questions from a professional perspective. They will discuss limits of theoretical models as well as alternatives to circumvent these issues. They will also explain how more complex structures are valued in practice.