Having been written by the same anonymous author, who was identified as Luke later in the second century, both
Luke and
Acts tend to flow quite well, with little overlap.
One important detail in which the two books overlap is in the ascension of Jesus. In Luke's Gospel (24:50-51), Jesus was seen to rise bodily up into heaven near Bethany on the very evening of his resurrection. When 'Luke' wrote Acts of the Apostles, for some reason he altered this to forty days after the resurrection (1:3).
Some of the material in
Acts seems to be inspired by earlier material in
Luke. Some scholars believe that in
Acts the trial of Stephen bears close parallels to the trial of Jesus in
Luke.