Between 7 March 2002 and 15 June 2002, an intensive multiwavelength campaign was carried out on the extreme BL Lac object H1426+428. Previous measurements have indicated that the synchrotron peak of H1426+428 lies in excess of 100 keV. At a redshift of 0.129, this active galactic nucleus (AGN) provides us with an excellent opportunity to study the properties of the extragalactic medium through which the radiation must propagate, as well as the properties of the AGN acceleration mechanism itself. By taking frequent observations over a four-month campaign, which included ∼450 ksec of RXTE time and >107 h of Whipple on-source time, it was possible to obtain data that can be used to search for correlations on multiple timescales. The 3-24 keV X-ray spectra exhibited variability, signifying variability in the location of the first peak of the spectral energy distribution, while the TeV emission above ∼390 GeV remained relatively low.