Selby's historic break came in the seventh frame of his semi-final match against Ricky Walden at the York Barbican. The maximum is worth £55,000 from the rolling prize for ranking events plus an extra £4,000 for the high break, as long as it is not equalled in the remainder of the tournament.
Defending champion Selby got the pack of reds open early in the break and picked them off with blacks before taking the colours. He played a superb shot on the brown to go around the angles and finish on the blue. The pink was tricky, played with his cue extension, and he left the cue ball on the top cushion. But Selby rolled a brilliant black into a centre pocket to complete the 147.
Given the circumstances, it must be considered one of the best ever blacks to finish a maximum - especially as he missed the last black on 140 at the China Open last season.
It's the third maximum of the season, following Neil Robertson at the Wuxi Classic qualifiers and Judd Trump at the Antwerp Open. And it's the second of 30-year-old Selby's career having made one at the 2009 Jiangsu Classic.
World number two Selby added the next frame to lead Walden 6-2 and move within three frames of a UK final against Neil Robertson.
The defending champion started the match well and took the opening two frames, a 69 break in the first, before winning a battle on the colours to seal the second on the final black (Mark Rawlinson writes).
Walden pulled back a closely contested second with a break of 56 but the Chester man missed the final brown in frame four to see Selby take a 3-1 interval lead.
Walden won the next with a top run of 43 but a missed pink in the sixth frame allowed Selby to restore his two-frame cushion at 4-2.
Selby then took centre stage with the 147, and a break of 53 was enough to secure the last frame of the session.
Snooker's first official 147 was made by Steve Davis at the 1982 Lada Classic. The following year, Cliff Thorburn made the first in the World Championship.
There were just eight maximum breaks in the 1980s but since then the standard of play in snooker has risen dramatically. During the 1990s there were 26 maximums, followed by 35 from 2000-2009 and another 31 maximums since 2010.
Ronnie O'Sullivan and Stephen Hendry share the record for the most maximum breaks with 11 each. John Higgins has made seven and Ding Junhui 5.
There have been ten 147s in the World Championship at the Crucible; three apiece from Hendry and O'Sullivan and one from each of Cliff Thorburn, Jimmy White, Mark Williams and Ali Carter
O'Sullivan made the fastest 147 on record at the Crucible in 1997, timed at 5 minutes and 20 seconds
The highest possible break in snooker is actually 155, if the player is awarded a free ball before a red has been potted. Only one break over 147 has ever been made in professional play, by Jamie Burnett who made a 148 at the 2004 UK Championship qualifiers. This did not count as a maximum break.
The youngest player to make an official 147 is Thailand's Thanawat Tirapongpaiboon, who did so in a 2010 PTC event, age of 16 years and 312 days.
Ball by ball scoring and results from tournaments