The Gunners took the lead in the first minute, added a second before half-time and the result was never in doubt after that.
Reading showed enthusiasm, commitment and hard work but the truth is that they were outclassed by a performance that was good enough for a night of European football.
Until beaten by a freak goal against Chelsea last week Reading had gone 14 months without a home defeat, but they were never given a glimpse of a possible victory by the team from north London.
Henry showed what was in store before most of the Reading team had even had a chance to touch the ball.
Tomas Rosicky shrugged off a challenge by former Arsenal youngster James Harper and squared the ball across the face of goal from the right wing. Reading's defence froze in horror as they realised Henry had the time and space to finish with clinical precision.
Despite this setback Reading battled away and Arsenal's Jens Lehmann was forced to make a magnificent save when Ki-Hyeon Seol volleyed the ball goalwards after the German had punched a corner clear.
But that was the closest Reading came throughout the entire game and six minutes before the interval Arsenal went further ahead.
Rosicky and Alex Hleb exchanged passes before Hleb slammed in the Gunners' second.
At half-time, Reading manager Steve Coppell replaced Ulises De la Cruz with Brynjar Gunnarsson at right-back, but it made little difference.
Five minutes into the second half Arsenal tore the Reading defence apart again. Henry slid the ball to Hleb, who cut inside to set up the chance for Robin van Persie to put the visitors further ahead.
Twenty minutes from time Arsenal completed their sixth successive Premiership win from the penalty spot.
Henry sent Cesc Fabregas through on goal. He tangled with Reading goalkeeper Marcus Hahnemann, who pulled him down, giving Henry the chance to score from the penalty spot - although the ball hit the upright on the way in.
Arsenal had lined up in the formation they normally use for European games, flooding the midfield with five players against Reading's four, and the Berkshire side were never really able to cope with this.
They clearly missed the influence of injured skipper Graeme Murty and striker Dave Kitson.
It was a reflection of the fact that Coppell still needs to strengthen his squad and will probably be keen for the January transfer window to arrive.
Wenger, on the other hand, is seeing his youngsters mature into a superb side, who earned warm applause from a Reading crowd that acknowledged it was watching a great performance by a great team.
The Royals will be relieved that they have now faced Manchester United, Chelsea and Arsenal in three successive home games and got them out of the way.
Their next league fixture is at Portsmouth, where they will hope to get back to winning ways.