The Nimbus-4 BUV Level 2 High-Density Ozone Data collection contains the vertical distribtuion and total column amount of ozone, as well as the full set of ancillary information. Each file contains total ozone, reflectivities, ozone mixing ratios and layer ozone amounts measured every 32 seconds during the daylit portion of an orbit. Mixing ratios are given at 19 levels: 0.3, 0.4, 0.5, 0.7, 1, 1.5, 2, 3, 4, 5, 7, 10, 15, 20, 30, 40, 50, 70 and 100 mbar. Layer ozone amounts are provided at 12 layers: 0.24, 0.49, 0.99, 1.98, 3.96, 7.92, 15.8, 31.7, 63.3, 127, 253, and 1013 mbar (bottom of layer value). The data collection also contains quality flags, orbital information, and housekeeping data. The data were originally created on IBM 360 machines and archived on magnetic tapes. The data have been restored from the tapes and are now archived on disk in their original IBM binary file format. Each file contains about one orbit of data. The files consist of data records each with two hundred and seven 4-byte words. The first record is the header record, followed by a series of data records, and ends with several trailer records that pad out the original blocked records. A typical orbit file is about 96 kB in size. The BUV instrument was operational from April 10, 1970 until May 6, 1977. In July 1972 the Nimbus-4 solar power array partially failed such that BUV operations were curtailed. Thus data collected in the later years was increasingly sparse, particularly in the equatorial region. This product was previously available from the NSSDC as the Total and Profile Ozone Data (HDBUV) with the identifier ESAC-00030 (old ID 70-025A-05Q).