This lecture explores the combination of lightcone conformal truncation with the S-matrix bootstrap method to compute physical observables in quantum field theory at strong coupling, focusing on the numerical solution of RG flows, the S-matrix bootstrap constraints, and the computation of spectral densities and form factors. The instructor discusses the application of these methods to various theories, such as the free massless scalar theory and the Ising model, highlighting the importance of model-dependent data and model-independent constraints in understanding the behavior of quantum field theories.