As Kun has steadily climbed the list, only Brook has scored more than the Blues’ talismanic striker.
Brook scored 177 goals in 453 appearances for City between 1928 and 1940 and he has led the scoring charts since overtaking Tom Johnson’s total of 166 with a goal away to Bradford City in September 1938.
Brook’s 79-year reign at the top will almost certainly remain intact for a while longer, too.
With only four games remaining, Sergio would need to score a goal glut that would be special even by his standards to overhaul Brook this season with a deficit of 10 to make up.
But if he avoids injury, particularly in the opening weeks of the 2017/18 campaign, Aguero could take over at the summit as early as the end of September.
If he does, it will be an incredible achievement by a very special player.
And if he can overhaul Brook within the next 10 games or so he plays, he will have done it almost 200 games fewer, too.
But as his record was set so long ago, many City fans are wanting to discover more about Brook and his prolific career with the Blues.
There is no doubt Brook was a special player and a fantastic signing for City.
A left-winger by trade, Brook rarely stayed on the flanks and considered the position as somewhere to find his bearings but any right-back hoping to man-mark Brook from start to finish would likely leave a big hole on one side of the defence as the City ‘winger’ had a licence to roam – and roam he did.
Brook cut a powerful figure and was physically imposing and strong.
He possessed one of the most powerful shots of his era and would regularly thump home penalties with venom.
Though he won just 18 England caps, many believe he was one of the best players of the late 1920s and 1930s and that perhaps he didn’t get the recognition he deserved.
Born in Mexborough, Yorkshire in 1907, Brook signed for Barnsley as a teenager and remained with the Tykes for three years before City came in with an offer of £6,000 for Brook and his team-mate Fred Tilson in March 1928 – an inspired move by manager Peter Hodge with Tilson’s 132 career goals for the Blues meaning the pair would net an incredible 310 goals between them in a combined appearance total of 726 matches – not bad value for money!
Brook and Tilson joined Tom Johnson, Billy Austin and Frank Roberts to form one of the most lethal forward lines in English football and though he only made 12 starts, Brook played his part as the Blues won promotion from Division Two.
Brook quickly became integral in City’s side, scoring 14 goals in 42 league appearances during his first full campaign at Maine Road and achieved double figures in goals during his first five seasons, rarely missing a game.
But for Arsenal’s Cliff Bastin, he would likely have doubled his appearances for England, but the pair were considered too similar in their style and only played in the same side a few times.
City lifted the FA Cup in 1934 with Brook assisting the winning goal for Tilson and were crowned champions of England in 1937 and Brook rarely missed a game in either campaign and scored twice in the 4-1 win over Sheffield Wednesday at Maine Road to clinch the title, watched by a crowd of more than 55,000.
Maybe only as City could back then, the Blues outscored every other side in the top flight but were relegated as defending champions – the only time this has ever happened in English football – and the 1938/39 campaign in Division Two would be Brook’s last full season for the Blues.
He played three games of the 1939/40 season before World War 2 meant the league was suspended. Though he made a handful of wartime appearances in 1939, a car crash left him with a fractured skull and, unable to head the ball again, he retired at the relatively young age of 32.
Unable to resume his career as many of his peers did after the war, Brook instead found other employment outside of football, working as a coach driver. Bar man and crane operating before passing away aged just 57 at his home in Wythenshawe.
At the time, Brook has been somewhat forgotten by football and his achievements consigned to the history books.
How fitting, then, that the name of Eric Brook is once again being talked and written about by the football world and who better to wrestle the mantle of greatest Manchester City goal-scorer than Sergio Aguero?
For now, however, it is Brook who still sits at the top of the pile…
