Introduction

In this chapter, we describe our motivation for writing this text, who will prot by reading it, and what it contains.

Modern 21st century biology is a complex discipline. Its descriptions involve the interactions of hundreds of thousands of different molecules (proteins, nucleic acids, hormones, cytokines, transcription factors, and other control substances). Its complexity became more apparent toward the end of the 20th century as instrumental techniques became available to efciently separate and analyze proteins, sequence genes, and examine the roles of RNAs and enzymes in the regulation of gene expression.