Which problems of physics and astrophysics are currently regarded as the most important and most interesting? (Thirty years later, virtually on the verge of the 21st century)

In this review of what he considers most interesting in contemporary physics and astrophysics, the author identified the following 30 topics as 'especially important and interesting problems of the year 1999': (1) Controlled nuclear synthesis. (2) High-temperature and room-temperature superconductivity. (3) Hydrogen metal. Other exotic substances. (4) Two-dimensional electron liquid (anomalous Hall effect and some other effects). (5) Some problems of solid state physics (heterogenous structures in semiconductors, metal-dielectric transitions, charge waves and spin densities, mesoscopics). (6) Phase transitions of the 2nd kind and related transitions. Some examples of such transitions. Cooling (laser cooling in particular) down to extremely low temperatures. Bose-Einstein condensation in gases. (7) Physics of surfaces. Clusters. (8) Liquid crystals. Seignetoelectrics. (9) Fullerenes. Nanotubes. (10) Behavior of matter in high-intensity magnetic fields. (11) Non-linear physics. Turbulences. Solitons. Chaos. Strange attractors. (12) Rasers, gasers, high-intensity lasers. (13) Superheavy elements. Exotic nuclei. (14) Spectrum of masses. Quarks and gluons. Quantum chromodynamics. Quark-gluon plasma. (15) Unified theory of weak and electromagnetic interactions. W± and Z0 bosons. Leptons. (16) The standard model. Grand unification. Super-unification. Proton decay. Mass of the neutrino. Magnetic monopoles. (17) Fundamental length. Particle interactions at high and very high energies. Colliders. (18) Non-conservation of CP-symmetry. (19) Non-linear phenomena in a vacuum and in high-intensity electromagnetic fields. Phase transitions in a vacuum. (20) Strings. M-theory. (21) Experimental testing of general relativity theory. (22) Gravitation waves and their detection. (23) The cosmological problem. Inflation. A-term. Relationship between cosmology and high energy physics. (24) Neutron stars and pulsars. Supernovae. (25) Black holes. Cosmic strings (?). (26) Quasars and galaxy nuclei. The origin of galaxies. (27) The problem of dark matter and its detection. (28) The origin of cosmic rays at very high energies. (29) Gamma flashes. Hypernovae. (30) Neutron physics and astronomy. The neutrino oscillation. The author comments on some of the problems of macrophysics and microphysics. (P.A.)