The last years have seen a symbiosis of the fields of elementary particle physics & the astrophysics of the early universe This text presents the background of the subjects & the latest developments at a level suitable for final year undergraduates & beginning graduate students The first chapters cover the properties & interactions of elementary particles followed by discussion of the early universe including inflation dark matter & dark energy & the growth of the galactic structure The final chapters discuss cosmic rays & particle physics in the stars The close relation between particle interactions & large scale development of the cosmos is a constant theme in the text with emphasis on the interplay between experiment & theory This book is an enlarged & updated version of the first edition published five years ago In a rapidly evolving field emphasis has of course been placed on the most recent developments However the opportunity has also been taken to re-arrange the material & present it in more detail & at somewhat greater length