After the drama and excitement of the World Cup, the transfer market is now the biggest game in European football. The summer transfer window for the 2018/2019 season will in future be known as the summer of goalkeepers.It is hard to recall a transfer window that has seen as many goalkeeping transfers as this one and more are still expected.After the unending (and frankly tiresome stream) of rumours constantly linking David De Gea to Real Madrid, it will finally be ended this season.The list of confirmed transfers is already mind-boggling; Martin Hardecky has joined Bayer Leverkusen to replace Bernd Leno, Marvin Hitz to Borussia Dortmund, Pepe Reina has joined AC Milan and the legend himself; Gigi Buffon has joined PSG.It's widely expected that Thibault Courtois' move to Real Madrid will trigger a game of musical chairs. Leicester City's Kasper Schmeichel is the alleged replacement at Chelsea while Danny Ward is expected to leave Liverpool and become the new numero uno for the Foxes.With the goalkeeping transfer record already broken, more moves involving top clubs and goalies are still being expected.Here is a look at 5 of the top goalkeeping transfers that may define the 2018/2019 season:#5 Bernd Leno (Bayer Leverkusen to Arsenal)Leno is expected to be the new number one at ArsenalArsenal fans could be forgiven for the optimism they felt when Petr Cech was signed in 2015.The move has not panned out as expected due to a combination of factors; Arsene Wenger's poor defensive tactics among others. This informed the decision by the new Arsenal manager Unai Emery to go for a new top goalie.Lots of names were bandied about but Gunners' chief scout Sven Mislintat's knowledge of the Bundesliga convinced the manager that Leno was the right choice.The German goalie who came in for a reasonable fee of £19.2m is expected to compete with Cech for the number one spot.He's a keeper 😁#HeyLeno pic.twitter.com/iGDIhOt5Ah— Arsenal FC (@Arsenal) June 19, 2018His agility, flexibility, command of his area and relative youth (26) means that the Gunners would have a reliable presence in goal for the next few years.At 1.9m, Leno keeps in tradition with the German style of producing tall goalies and is more than capable of producing the goods for Arsenal. Quick of his line, he is agile and capable of making breathtaking saves (and a few clangers but nothing on the David Ospina and last season’s Cech scale).