Leslie Leland Locke (1875–1943)[1] was an American mathematician, historian, and educator, best known for his work on deciphering ancient Andean knot records called quipus.

[5] In 1933, Locke joined Brooklyn Technical High School as a mechanical drawing instructor, a role he held until his retirement in 1942.

[6] Notably, an accession card for quipu B/8715 in the museum's collection indicates that the specimen was lent to Smith in November 1911, likely for Locke's research.

[10] Locke later expanded his initial 1912 article into a full-length book, publishing The Ancient Quipu or Peruvian Knot Record through the American Museum of Natural History in 1923.

Early reviews hailed the book as "the first serious attempt to elucidate the quipu mystery"[11] and noted that "the conclusions reached by Professor Locke are very important.

"[12] In the preface to one of his own works on quipus, Erland Nordenskiöld—a leading expert in South American archaeology and anthropology of the early 20th century—praised Locke as "the founder of the modern study of the quipu".

The central image depicts a figure, possibly seated or standing, engaged in scholarly or artistic activity, with a detailed rectangular object below that may represent a table, altar, or chest.

He also preserved lecture notes from his time as both a student and a mathematics teacher, providing insight into early 20th-century educational practices.

[5] However, one source also notes that Locke donated "valuable early American text-books" to the University of Michigan during his lifetime.