Hittite festival texts, the largest among the groups of documents in the libraries of Hattusa, are extremely lengthy compositions. Previous studies have either given general overviews of whole festivals, or have chosen individual tablets for in-depth philological investigations. This is the first comprehensive study of a large festival text, revealing its basic threepart structure: a detailed scenario of the festivities, the liturgy recited, and the logistic directives. The "Gatehouse (KI.LAM) Festival" lasted for three days and included pompous processions to public buildings in the capital (temples, palaces, magazines) and its vicinity. It culminated in a great assembly held at a sacred locale outside the city, with celebrations dedicated to all the gods, with feasts and sports events. The commentary (Part I, ISBN 978-3-447-02243-9) focuses on matters pertaining to the ancient topography of Hattusa (and nearby Yazilikaya), the cultic insignia carried along in the ceremonial procession, and the rations allotted to the participants (food, festive garments and ornaments). The restored text included in this volume comprises about one hundred fragments belonging to different redactions of the text; they were written in the Old, Middle and Late Hittite scripts.