"Do codons overlap? In other words, as we read along the genetic message do we find a base which is a member of two or more codons? It now seems fairly certain that codons do not overlap"

This quote by Francis Crick is going over the concept of codon overlap. A codon is a series of three nucleotides that form a system of genetic code in a DNA or RNA molecule. The question presented by Crick is whether or not codons overlap, indicating if a single base is a member of two or more codons. Crick suggests that it is now particular that codons do not overlap. This means that each base in a codon is unique and is not shared with any other codon. This is necessary because it permits the hereditary code to be precisely read and analyzed. Without codon overlap, the genetic code can be precisely translated into proteins, which are necessary for life. This quote by Francis Crick is a crucial suggestion of the value of codon non-overlap in the hereditary code.