Derived categories (DER) Forum organised by Reid and Szendroi (advised by Bridgeland) This is a technical area linking category theory, geometry, algebra and theoretical physics that has had tremendous band-wagon appeal in the last 10 years. Areas of advance include McKay, MMP, homological mirror symmetry, the Fukaya category in symplectic geometry, stability conditions for D-branes, moduli spaces, noncommutative geometry, representation theory, the Brou\'e conjecture (in modular representation of finite groups). These ideas will be somewhere in the background of most WAG07-08 activities. The subject is however marked by an unfortunate tendency for abstract ideology to dominate over problems, and by the (sometimes misleading) preconception that questions must be expressed in derived category terms. After consultation, we have decided that rather than a workshop or conference, we want to bring together specialists in different aspects of derived categories and its applications for a forum concentrating on what one can do and what one can't do with these ideas (probably lasting 3 days over a weekend in summer 2008). Targetted participants (some of): Bondal, Bridgeland, Caldararu, CHEN Jiun-Cheng, Colin Ingalls, Eisenbud, Fantechi, Grojnowski, Haiman, Ian Gordon, ISHII Akira, Joseph Chuang, Joyce, Kaledin, Katzarkov, Kawamata, Ken Brown, Kresch, Kuznetsov, Mukai, OKADA So, Orlov, Rickard, Rouquier, Rumynin, Schofield, Seidel, Stafford, Szendroi, Thomas, TODA Yukinobu, Bernard Toen, UEDA Kazushi, UEHARA Hokuto, van den Bergh, Vistoli,