The 7,000 GAL4 driver lines in this collection were constructed by the methods described in Pfeiffer BD, Jenett A, Hammonds AS, Ngo TT, Misra S, Murphy C, Scully A, Carlson JW, Wan KH, Laverty TR, Mungall C, Svirskas R, Kadonaga JT, Doe CQ, Eisen MB, Celniker SE, Rubin GM. Tools for neuroanatomy and neurogenetics in Drosophila. Proc Natl Acad Sci U S A. 2008 105:9715-20. These lines differ from standard enhancer trap lines in that a defined DNA fragment drives GAL4 expression and all the constructs are inserted into the same genomic location, the attP2 site at 68A4 on 3L, by site-specific recombination. In general, these lines express GAL4 in more restricted patterns than observed with standard enhancer traps. Barret Pfeiffer, Chris Murphy and Heather Dionne in the Rubin laboratory at Janelia Farm were the lead individuals in constructing the lines, working with the Berkeley Drosophila Genome Center (managed by Sue Celniker) who sequence verified the constructs, Genetic Services Inc. who performed embryo injections, and the Janelia Farm Fly Facility (managed by Todd Laverty) who generated the homozygous (or balanced) stocks. Additional individuals who contributed to this work include: Rubin Lab: Teri Ngo, Arnim Jenett and Aljoscha Nern. Janelia Farm Fly Facility: Karen Hibbard, Amanda Cavallaro, Don Hall, Monti Mercer, Megan Hong, Grace Zheng, Jessica Keating, Dona Fetter, James McMahon and Jui-Chun Kao. Genetic Services, Inc: Susan Zusman and Mike Tworoger. Berkeley Drosophila Genome Project: Joe Carlson and Ken Wan. Janelia Farm Scientific Computing Group: Rob Svirskas.