This is the "heart" of the Kittel text. It explains why some materials conduct electricity while others do not.
Many top-tier universities (MIT, UC Berkeley, IITs) have open-source lecture slides based on Kittel. Search for: introduction to solid state physics kittel ppt updated
Moving from real space to the Reciprocal Lattice. This is the "heart" of the Kittel text
Charles Kittel's "Introduction to Solid State Physics" is a classic textbook that has been widely used for decades. The book provides a comprehensive introduction to the field, covering the fundamental concepts and principles of solid state physics. The updated version of the book, now in its 8th edition, includes new topics and recent developments in the field. now in its 8th edition