Ash: A Secret History

Precedence here is genuinely split. The complete novel first appeared as one volume from Gollancz in the UK in 2000. However, the US Avon Eos paperback split released its first volume, titled A Secret History, in 1999, ahead of the UK single volume, with the remaining three volumes (Carthage Ascendant, The Wild Machines, Lost Burgundy) following in 2000. So the UK Gollancz 2000 is the first single-volume edition, but it is not the first appearance of the opening text in print. Ash won the 2000 BSFA Award for Best Novel and the 2001 Sidewise Award for Alternate History.