This book reviews the present status of our understanding of subnuclear phenomena. The opening lecture, by G't Hooft, reaches the limits of our imagination in particle physics. A group of lectures by F Wilczek, D Nanopoulos and G Altarelli discuss the physics beyond the Standard Model. A Masiero reviews the problem of FCNCs which are not there in spite of Susy. Superstring and M-theory are discussed by M B Green, while S Glashow presents some puzzles in particle physics. The possible sources for new physics coming from new experimental results are presented by H Satz, G Wolf, G Kane and Y Totsuka. The high precision electroweak data are reviewed by M Pepe-Altarelli and the most recent LEP results by S Katsanevas. A Linde and G Veneziano bring the reader into the field of inflationary and pre-big-bang cosmology. A Zichichi reports the first evidence for the leading n' production in gluon-induced jets and gives a summary of subnuclear physics during the past 50 years, With a projection of the Eloisatron Project. The closing lecture is presented by T D Lee.