This is my list of 12 most difficult bowlers to face for batsmen in order of merit.Not ranked in order of merit but just in regard to how hard they were to face or basically lethal. Wasim Akram Malcolm Marshall Dennis Lillee Andy Roberts Michael Holding Jeff Thomson Glen Mcgrath Shoaib Akhtar Richard Hadlee Imran Khan Curtly Ambrose Dale Steyn Alan Donald Waqar Younus Courtney Walsh Wasim simply had every attribute and was the ultimate magician who was impossible to gauge with his art of reverse swing.The likes of Viv,Kallis and Lara rate Wasim the hardest pace bowler they ever faced.Not as accurate as Ambrose or Mcgrath or as quick as Marshall but in a total package the most complete. Marshall's mastery of skidding the ball surpassed everyone and a batsmen could not tell whether the ball was moving in or out as he never changed his action. Lillee took hostility to its highest zenith with the most organised repertoire of the outswinger,leg-cutter and bouncer. Lindwall was faster and had more control than Lillee with a more effective outswinger.Yet not as determined.Alan Davidson,Trueman and Denis Compton rated him ahead of Lillee. Roberts was the the Lillee of his day with 2 bouncers at different speeds,an ouswinger and an offcutter.Weakness was that he did not have a good yorker.Unlike Lillee proved himself on slow subcontinent tracks.Gavaskar and Lillee rated Roberts the best fast bowler of his day. Michael Holding consistently posessed more speed through the air than any fast bowler and could obtain pace and bounce on the flattest surfaces.Not surprising that he has bowled the greatest spell and over in history of test cricket.Posessed the most perfect action of all and was a master in making the ball bounce so near the bat. Mcgrath mastered weakness of opponents better than any paceman and was a master in all conditions.Noone had more control.No paceman put the ball more perfectly in the corridor as Glen,or with such consistency. Jeff Thomson intimidated opposing batsmen more than anyone producing the most devastating speed at his fastest .He made the ball disconcertingly or alarmingly rise from a good length to hit a batsmen's gloves or even head. Shoaib Akhtar was like a re-incarnated Jeff Thomson who could reverse swing a ball,surpassing anyone electronically. Imran's pace and movement were unplayable on his day.Had the most lethal inswinger. Hadlee was the most lethal on a green top resembling a computerized machine and had equal control as Mcgrath ,with higher speed and movement.Rated lower than some because he could become defensive when attacked,particularly on flat wickets. Ambrose could rip of the flesh of a batting line up better than anyone on a bad wicket,like a cowboy mowing down his opponents in a shoot.None was as relentless or accurate whose vertical bounce could be unplayable. Dale Steyn was similar to Marshall with mastery in skidding a ball but not as adept in swinging the ball in. Alan Donald substantiated lightning pace with subtle verstality and control. Waqar was the best ever exponent of the swinging yorker and in terms of speed in the Jeff Thomson league. Courtney Walsh was the ultimate metronome who had a strong element of unpredictability and a master on slow tracks in the sub-continent.