Byte Pair Encoding (BPE) was introduced in 1994 as a data compression technique by Philip Gage.Initially used for compression, BPE's adaptive nature later found applications in NLP, particularly in tokenization.In NLP, BPE tokenizes text into subword units by iteratively merging the most frequent pair of adjacent symbols.BPE balances between word-level and character-level tokenization, preserving word fragments while decomposing rare words.The method involves merging frequent symbol pairs to create a vocabulary of subword units reflecting language patterns.Efficient for language models, BPE optimizes sequences and balances computational load, memory requirements, and generalization.BPE's utility lies in its ability to handle diverse vocabularies, making it suitable for various languages and domains.BPE's success is attributed to its pragmatic approach of optimizing trade-offs, rather than just focusing on a single objective.The merge table in BPE stores symbol pairs for consistent tokenization of new words based on training data patterns.BPE exemplifies how simple, repurposed algorithms can form the foundation of advanced AI models like GPT-3 and GPT-4.