This book is a tribute to Professor Abdelhak Ambari and brings together ten chapters written by colleagues who were fortunate enough to work with him. The contributions presented in this book cover the research themes in which Abdelhak Ambari was interested, and to which he made valuable experimental and theoretical contributions. For example: rheology of complex fluids and polymers; hydrodynamic interactions; flows at low Reynolds numbers; characterization of porous media; hydrodynamic instabilities and solid mechanics; electrochemical metrology. Some Complex Phenomena in Fluid and Solid Mechanics is aimed at a wide community of readers wishing to delve deeper into these scientific themes: since it is oriented toward the world of research, it will be a valuable tool for doctoral students and beyond. The book also provides undergraduate and graduate students with a good introduction to the techniques and approaches developed in fundamental and applied research in the fields of fluid mechanics, solid mechanics and instrumentation.