This document provides an overview of MARC 21 bibliographic records, focusing on commonly used fields for physical description and publication information. It discusses the 260 (publication, distribution, etc.), 300 (physical description), 310 (current publication frequency), and 321 (former publication frequency) fields in detail, including proper subfield coding and punctuation. Examples are provided for how to record multiple publishers, dates, physical formats and accompanying material. The document also clarifies the differences between MARC 21 and AACR2 rules and concludes with an assignment linking to additional online training materials.