In 1784, a year of crisis in which he suffered and recovered from serious illness, Mozart started keeping a record of all his compositions, perhaps as part of an attempt to introduce some order into his hectic, irregular mode of life. This notebook, his Thematic Catalogue, stayed by his side and was kept up to date right up to his death in 1791. To mark the 200th anniversary of that event, the British Library's manuscript is reproduced here in two-colour facsimile. Albi Rosenthal provides a general introduction, placing the document in the context of the composer's life, while Mozart scholar, Alan Tyson, gives a detailed commentary and transcription. Albi Rosenthal is a dealer in rare books and manuscripts. Alan Tyson is a Fellow of All Souls, Oxford.