This directory provides paths to several IMP 8 magnetic field data sets. There are three 15.36s data sets. The first, in ...15s_ascii_old, was created in 2002 and was passed through NSSDC's DIOnAS process for long-term archiving. The second, ...15s_ascii_v2, was created in 2008 to fix end-of-day record-dropping problems for a very few days in the 2002-created version. See the readme files in these directories to more fully understand their content, differences and relation to yet earlier data. The third 15.36s data set, ...15s_ascii_v3, is wholly new data set created in 2009 mainly by taking averages over newly cleaned 320ms data, with a 6% admixture of newly cleaned v2 data for >30min intervals of no 320ms data or inferior 320ms data. See the readme in this subdirectory for further details. There is a subdirectory (...1min_ascii) with 1-min values calculated by the PI team for the ISTP era (1991-2000). There is a subdirectory for hourly averaged, solar wind only, magnetic field data computed in January, 2010, from newly processed higher resolution magnetic field data. It replaces an earlier data set. The previously available hourly data set for all IMP 8 orbit phases has been deleted as being of marginal value. There are links to (a) 1-min, bow-shock-nose-shifted magnetic field and plasma data accessible via omniweb and used in the creation of the high Resolution OMNI data set and to (b) 320ms data accessible from omniweb's ftp area. Note that there is also a field-plasma-merged 1-min data set, spanning 1974-2000, created in 2010 using reprocessed (version 3) 15.36s magnetic field data, at https://spdf.gsfc.nasa.gov/pub/data/imp/imp8/merged/ ----------------------------------------------------------------------------