Numbers are the code of universal harmony, divine creation, magic, and also of scientific rationality, calculation and method. Cryptic knowledge is perfectly expressed in numbers, as if they were the emanation of a mathematical God. Our age pays little heed to numerology, but is obsessed with quantification and statistics, which have become the main tool of governance, rankings, ratings and generalised evaluation as a way of managing human and material resources. It is precisely because numbers are now so dominant and powerful (to the extent that politics has become a mere province of the wider economy), that Electra is devoting the ‘Subject’ section of this issue to this area. Here you will find articles about the philosophy of number, forms of digital art, modern governance through numbers, and the history of algorithms and their function in digital networks. These compulsory stops shine light on a variety of incursions into a vast universe that continues to expand in our age - the digital age. All the images dedicated to Numbers in this issue are by António Sena. Throughout a career that spans over five decades, signs, numbers and letters represent his attempts – successful or not – to interpret the world and everything that happens in it. His work also questions the demands, potentialities and illusions of human communication in all its variety of languages. In inviting António Sena to collaborate, Electra recognises an artist who, through his intellectual research and artistic practice, and integrity and persistence, has created a body of work with a considerable formal coherence that is unique in the world of contemporary art.