An automatic manual transmission comprising a first plurality of gear pairs (42/52, 44/54, 46/56) which forms a first power transmission path to transmit the power of the engine to the output of the transmission, in which each gear pair (42/52, 44/54, 46/56) defines a respective transmission ratio; and said first plurality of gear pairs comprises all the even-numbered gears (2nd, 4th, 6th); a second plurality of gear pairs (41/51, 43/53, 45/55) which forms a second power transmission path to transmit the power of the engine to the output of the transmission, in which each gear pair (41/51, 43/53, 45/55) defines a respective transmission ratio; and said second plurality of gear pairs comprises all the odd-numbered gears (1th, 3rd, 5th); one or more output shafts (16); one or more intermediate shafts (71, 72, 73) each of which is coaxially and rotatably mounted either to an input shaft (11, 12) or to an output shaft (16) and kinematically interposed between the output shaft (16) and an input shaft (11, 12); wherein said first power transmission path is connected and disconnected to and from the output of the transmission by means of a first synchronization and engagement device (S1), and said second power transmission path is connected and disconnected to and from the output of the transmission by means of a second synchronization and engagement device (S2).