Based on the publication of a vast body of material hitherto only partially known to the general public, this book sets out to graphically document and describe Miro's creative process in terms of the essential laws of its function. It is not simply the pre-history of each work, but rather its real history: here we see how a work by Miro becomes reality, is born, and reveals what we might call its innermost secrets. The autor has conducted a detailled survey of the 4.556 sketches and preparatory studies that the great artist produced throughout his life and which in 1976 he donated to the foundation bearing his name in Barcelona. Ober 1.200 of theses pieces that belong to Miro's creative universe selected, reproduced, and analyzed by Pere Gimferrer, allow us to oberserve the artist's stringent work method, the laborious process which, despite appearances- given the spontaneous character of the final result - each work follows from its conception to its completion. In the presentation of the material, a chronological order has been followed, contrasting sketches with finished pieces, which thanks to Gimferrer's analysis in each case permits us to trace the guidelines leading from the preparatory study the final work. The book is completed by an extensive catalogue prepared by Rosa Maria Malet and featuring the technical data corresponding to each of the works reproduced.