Experts act without thinking because their skill is hierarchical. A single conscious thought automatically produces a series of lower-level actions without top-down monitoring. This article presents a theory that explains how automatic control is possible in skilled typing, where thinking of a word automatically produces a rapid series of keystrokes. The theory assumes that keystrokes are selected by a context retrieval process that matches the current context to stored contexts and retrieves the key associated with the best match. The current context is generated by the typist's own actions. It represents the goal ("type DOG") and the motor commands for the keys struck so far. Top-down control is necessary to start typing. It sets the goal in the current context, which initiates the retrieval and updating processes, which continue without top-down control until the word is finished. The theory explains phenomena of hierarchical control in skilled typing, including differential loads on higher and lower levels of processing, the importance of words, and poor explicit knowledge of key locations and finger-to-key mappings. The theory is evaluated by fitting it to error corpora from 24 skilled typists and predicting error probabilities, magnitudes, and patterns. Some of the fits are quite good. The theory has implications beyond typing. It argues that control can be automatic and shows how it is possible. The theory extends to other sequential skills, like texting or playing music. It provides new insights into mechanisms of serial order in typing, speaking, and serial recall. (PsycINFO Database Record