You probably already know that there is more than one fingering for many of the notes on the saxophone (see fingerings index on pages 210 to 213). By alternating between different fingerings of the same note, it is possible to get differences in tone.
Listen to the following example which features two different fingerings for the note Bb. The notes played with alternate fingerings have alt written above them.
It is possible to find alternate fingerings for some notes by simply playing the fingering for the note one octave below and adding the octave key. This applies to the following notes.
The alternate fingerings for the notes you have just learned can also be used to produce a note a 5th above the previous notes. This is similar to a trumpet player using the same fingering to produce different notes. Practice the following example slowly until you are confident you can produce the correct pitch for each note played with an alternate fingering.
Here is a solo which makes use of alternate fingerings. At the end of the book you will find a chart which lists alternate fingerings. Go through it and memorize all the fingerings and then experiment with them until you are comfortable using them in your playing.