In his four previous forays into the world of wheeling and dealing, the Celtic boss has found the window to bring some smashing successes – and provide some truly shattering lessons.

Celtic's financial situation demands Lennon operates at the level of the transfer market where gambles are the norm, and dead-certs outwith his reach.

To bring in the finished article would require the club to plunge into the kind of debt which has been anathema to them since they found themselves lumbered with a £30million shortfall towards the end of Martin O'Neill's tenure at Parkhead.

Seeing the imminent danger of the financial downturns, which caught out so many, a much more prudent approach was adopted from that point on through Gordon Strachan's era in charge.

The days of £6m signings and wages which made moving from the Barclays Premier League to the SPL attractive were gone forever.

The wage bill – which was at one time draining over 60% of the club's substantial income – was seen to be unustainable.

It was slashed, as was the fund from which the Celtic manager could draw for new players to replace the high earners who had moved on.

Basically, what was brought in from savings and sales could be reinvested, so the art of successfully operating in the transfer market has become more important than ever.

Lennon's own start in this field was funded by the departure of Aiden McGeady, Artur Boruc and Stephen McManus – in turn, the club's best player, the fans' favourite, and the captain.

Every penny was required because, after the debacle of Tony Mowbray's team transformation in the two windows he was at the helm, Lennon recognised the bulk of the squad inherited were not going to fit into the game plan he was about to introduce.

Mowbray recruited more than a team of players. He signed Marco Fortune, Landry N'Guemo, Lukasz Zaluska, Danny Fox, Josh Thompson, Zheng Zhi, Ki Sung-Yueng, Jos Hooiveld, Thomas Rogne and Morten Rasmussen.

In a desperate last throw of the dice as the 2010 January window closed, he swooped to add Edson Braafheid, Dio- mansy Kamara and, finally, Robbie Keane on loan.

Braafheid may have been on his way to play in the World Cup final for Holland, but the Dutch defender's loan to Celtic from Bayern Munich proved to be an expensive error, reputed to have cost the club around £35,000 per week.

At least Braafheid's drain on resources could easily be severed. Like his fellow loanees – who had proved much more productive short-term acquisitions – he disappeared from the club as soon as the trophyless season ended.

Lennon knew that others, signed on three and four-year contracts, would be harder to shift. Indeed, some are still on the pay-roll while contributing next to nothing.

Rasmussen – a £1.5m arrival from Brondby – and teenage defender Thompson proved not to be up to the task, and the Dane in particular remains a forlorn figure only just registering on the distant periphery of the squad.

Lennon's immediate remit was to remodel his squad, and he set about the task with gusto, with upwards of a dozen players who ended the season not being in the ranks when his first full campaign began.

In their places stood a group of men Lennon and his scouts had identified as capable of dragging the club up by its bootstraps, and hauling in a Rangers side who – unbeknown to most at the time – were riding high on the back of a financial blueprint which was about to explode with catastrophic effect.

Of course, while Lennon and chief scout John Park did their best to carefully identify targets, there had to be an element of buck-shot involved because so many players had to be delivered.

The vast majority of the new faces fitted the Identikit of being raw talent with the potential to be come gems.

Some, like Gary Hooper, Beram Kayal, Emilio Izaguirre, Joe Ledley and Anthony Stokes proved to be instant hits, while Kris Commons made the most immediate impact when he arrived in the January window.

Others, like Charlie Mulgrew and Fraser Forster, were slow burners, but this season have set the place alight.

James Forrest was a prodigious talent already at the club, and immediately promoted by Lennon from the youth team he had once coached.

At the other end of the age spectrum, Daniel Majstorovic was brought in on a cheap deal from Greece and Cha Du-Ri from Germany to add some much-needed experience to this fledgling group.

The return Lennon has received for his relatively-modest outlay has been impressive, as the delivery of the SPL title last season confirms.

But, of course, when you are dealing in such volume, there will always be signings which do not hit the mark.

Freddie Ljungberg's short and unremarkable stay has almost certainly warned Lennon off 'marquee' signings, while Efrain Juarez's disappointing impact remains a big regret for the man who sanctioned an outlay of around £2.5m for the Mexican.

Likewise, Daryl Murphy was brought to Parkhead with an international pedigree, but was quickly identified as a square peg at a round hole club.

One of Lennon's real strengths is his ability to recognise his mistakes and not obstinately persevere with them in the hope they will eventually come good and prove he was right all along.

Olivier Kapo and loanees Pawel Brozek and Badr El Kaddouri, immediately come to mind.

However, it can be a costly experience because it is seldom that players who fail to cut the mustard at your club are in particularly high demand from others.

Often, you have to bite the bullet and take the hit by off-loading unwanted players at less than their worth or what you paid for them.

Hooiveld was a case in point when he was shipped out to promotion-chasing Southampton, Murphy appears to be on his way to Ipswich for just £300,000 and Juarez is en route back to Mexico with around £2m written off, while the jury remains out on Kelvin Wilson and Mo Bangura.

However, as he prepares to spend some more of the club's money, Lennon's transfer dealings are very much in credit.

The value of the squad he has assembled is many, many millions higher than what it cost to bring them here, with men like Hooper and Kayal now carrying price tags upwards of £6m.

Last summer's recruits have also added substantially to the squad value. Victor Wanyama cost just £900,000 and is bracketed at around five times that after just one season at Parkhead.

Adam Matthews – like Ledley, a Bosman – is another with a value which grows with every passing week.

So, Lennon's strike rate is high, and he aims to improve it even further in this window, when quality rather than quantity will be his watchword.