AbstractThe present special issue of physica status solidi (b) is dedicated to Professor Dr. Jozef T. Devreese on the occasion of his 65th birthday. Professor Devreese from the Laboratory of Theoretical Physics of Solids at Antwerp University is a distinguished theoretical physicist with outstanding achievements in various areas of condensed matter physics over many decades. 40 contributions written by his colleagues, collaborators, and friends were assembled in this edition.The cover picture of this Liber Amicorum shows an artist's view of the polaron, originally sketched by Jozef T. Devreese for the cover of Ref. [1].