This chapter delves into advanced studies in boiling phenomena, focusing on interfacial instability, multimode bubble formation, and nanoscale heat transfer. The work is divided into two major sections: an analysis using the Coupled Level Set and Volume-of-Fluid (CLSVOF) approach to study interfacial instability and bubble dynamics in saturated pool boiling, and a molecular dynamics (MD) simulation to investigate boiling and evaporation in a liquid argon film on a platinum heater at the nanoscale. The first part illustrates a continuum-based simulation study to simulate boiling in a two-dimensional domain. The findings highlight key phenomena such as Rayleigh–Taylor and Taylor–Helmholtz instabilities and their impact on bubble formation and growth. The results demonstrate the transition from isolated bubble formation at low heat fluxes to complex multimode bubble dynamics at higher heat fluxes, including the transition to film boiling. This part also demonstrates the effect of external gravity and electric field on the bubble dynamics during film boiling. The second part utilizes MD simulation to explore atomistic mechanisms of heat transfer and phase change in a thin film of liquid argon. It basically shows the origin or initial stages of vapor bubble formation inside a bulk liquid phase. This study reveals the detailed processes of heat transfer, evaporation, and bubble nucleation, influenced by surface characteristics such as wettability. It shows that hydrophilic surfaces promote explosive boiling at lower superheats, while hydrophobic surfaces require higher superheats to initiate boiling. Comparing these two studies provides a comprehensive understanding of boiling phenomena across different scales. The CLSVOF approach offers macroscopic insights essential for engineering applications, while the MD simulation provides crucial nanoscale details. Integrating these scales can enhance predictive models and lead to the development of improved boiling surfaces and heat transfer systems, with significant implications for power generation, electronics cooling, and chemical processing. This chapter underscores the importance of multiscale modeling in advancing thermal management and energy systems.