Scientific Requirements and Prospects -- Prospects in space-based gamma-ray astronomy -- Annihilation of positrons in the Galaxy -- Prospects and requirements for measurements of extragalactic ?-ray lines -- Non-thermal cosmic backgrounds and prospects for future high-energy observations of blazars -- Rolling down from the 30 keV peak: Modelling the hard X-ray and ?-ray backgrounds -- Focusing supernova gamma rays -- Nucleosynthesis in nova explosions: Prospects for its observation with focusing telescopes -- Puzzles and potential for gamma-ray line observations of solar flare ion acceleration -- Gamma-ray Optics -- The INTEGRAL — HESS/MAGIC connection: A new class of cosmic high energy accelerators from keV to TeV -- Replicated nickel optics for the hard-x-ray region -- Small d-spacing WC/SiC multilayers for future hard X-ray telescope designs -- Design aspects of grazing angle multilayer mirrors for soft ?-rays -- Progress toward light weight high angular resolution multilayer coated optics -- InFOC?S hard X-ray imaging telescope -- Development of the HEFT and NuSTAR focusing telescopes -- The SIMBOL-X hard X-ray mission -- Laue diffraction lenses for astrophysics: Theoretical concepts -- Laue diffraction lenses for astrophysics: From theory to experiments -- Mosaic and gradient SiGe single crystals for gamma ray Laue lenses -- Copper mosaic crystals for Laue lenses -- High diffraction efficiency, broadband, diffraction crystals for use in crystal diffraction lenses -- An “ESA-affordable” Laue-lens -- Optical properties of Laue lenses for hard X-rays (> 60 keV) -- Development of a new photon diffraction imaging system for diagnostic nuclear medicine -- HAXTEL: A Laue lens telescope development project for a deep exploration of the hard X-ray sky (>60 keV) -- CLAIRE: First light for a gamma-ray lens -- MAX, a Laue diffraction lens for nuclear astrophysics -- The gamma ray lens — an ESA technology reference study -- Gamma ray Fresnel lenses — why not? -- Development of ground-testable phase fresnel lenses in silicon -- Multiwavelength focusing with the Sun as gravitational lens -- Focal Plane Instrumentation -- A Si/CdTe Compton Camera for gamma-ray lens experiment -- New scintillators for focal plane detectors in gamma-ray missions -- A focal plane detector design for a wide-band Laue-lens telescope -- Polarisation measurements with a CdTe pixel array detector for Laue hard X-ray focusing telescopes -- Simulated performance of dedicated Ge-strip Compton telescopes as ?-lens focal plane instrumentation -- Monte Carlo study of detector concepts for the MAX Laue lens gamma-ray telescope -- Performance of the Nuclear Compton Telescope -- The Compton and pair creation telescope MEGA -- Ground Facilities and Flight Systems for Focusing Telescopes -- The MPE X-ray test facility PANTER: Calibration of hard X-ray (15–50 kev) optics -- The Ferrara hard X-ray facility for testing/calibrating hard X-ray focusing telescopes -- SIMBOL-X: An hard X-ray formation flying mission -- Distributed space segment for high energy astrophysics: Similarities and specificites -- The CLAIRE gondola: Testing the first gamma-ray lens on a stratospheric balloon -- Recent advances and low cost concept for the gamma-ray lens project MAX -- Small-sat platforms and formation flying: An opportunity for the gamma ray telescope MAX -- MAX: Formation flying for nuclear astrophysics -- Formation flying for a Fresnel lens observatory mission.