The Kórmchaia Book, also known as the Books of the Pilot (Russian: Ко́рмчая книга, Ко́рмчая from кормчий, Church Slavonic: кръмьчии 'helmsman, ship's pilot'; Pidalion (Russian: Пидалион from Ancient Greek: Πηδάλιον, Πηδαλίων 'stern oar, helm, handle of helm, rudder') or Nomocanon (Russian: Номокано́н from Ancient Greek: Νομοκανών from νόμος 'law, statute' + κᾰνών 'canon, rule'), are collections of church and secular law (see also Byzantine law), which constituted guide books for the management of the church and for the church court of Orthodox Slavic countries and were also the transmission of several older texts.

The Kormchaia Book goes back to the Byzantine Nomocanon, composed in the 6th century by John Scholasticus, Patriarch of Constantinople.

[1][2] Nomocanons in Russian processing[clarification needed] were called Kormchaia Books at the end of the 11th century; they were supplemented in Russia by the norms of secular law.

It was also supplemented by Russian articles: Russkaya Pravda, the church statutes of the princes Vladimir and Yaroslav, the rules of the 1274 Council and others.

In the late 15th and early 16th centuries, the Kormchaia Books were revised due to the large number of variant readings.