This chapter addresses a basic integer encoding problem whose impact on the total memory footprint and speed performance of the underlying application is too easily underestimated or neglected. The problem consists of squeezing the space (in bits) required to store an increasing sequence of integers, and then supporting efficient query operations such as decompressing the sequence from the beginning or from some other position, checking whether an integer occurs in the sequence, or finding the smallest integer larger than the queried one. This problem occurs in several common applications, such as in the storage of the posting lists of search engines, or of the adjacency lists of trees and graphs, or of the encoding of sequences of offsets (pointers). The integer coders here discussed, analyzed, and illustrated with many running examples are Elias’ γ- and δ-codes, Rice’s code, PForDelta code, variable-byte code, (s, c)-dense codes, interpolative code, and, finally, the very elegant and powerful Elias–Fano code.