errors in code from book projects

I am completely new to this, so no solution is obvious to me. I have been working through the projects in the book ‘beginning arduino’, entering the code printed in the book. Occasionally error messages pop up and, when they are not my typos, I am lost on how to fix the problem. For example, in project 19-LED dot matrix display-basic animation, here is the code I entered:

//project 19
#include <TimerOne.h>

int latchPin = 8; //Pin connected to Pin 12 of 74HC595 (Latch)
int clockPin = 12; //Pin connected to Pin 11 of 74HC595 (Clock)
int dataPin = 11; //Pin connected to Pin 14d of 74HC595 (Data)

byte led[8]; // 8 element unsigned integer array to store the sprite

void setup() {
pinMode(latchPin, OUTPUT); // set the 3 digital pins to outputs
pinMode(clockPin, OUTPUT);
pinMode(dataPin, OUTPUT);
led[0] = B11111111; // enter the binary representation of the image
led[1] = B10000001; // into the array
led[2] = B10111101;
led[3] = B10100101;
led[4] = B10100101;
led[5] = B10111101;
led[6] = B10000001;
led[7] = B11111111;
// set a timer of length 10000 microseconds (1/100th of a second)
Timer1.initialize(10000);
// attach the screenUpdate function to the interrupt timer
Timer1.attachInterrupt(screenUpdate);
}

void loop() {
for (int i=0; i<8; i++) {
led_= ~led*; // invert each row of the binary image*_
* }*
* delay(500);*
}
void screenUpdate() { // function to display image
* byte row = B10000000; // row 1*
* for (byte k = 0; k < 9; k++) {*
* digitalWrite(latchPin, LOW); // open latch rready to receive data*
* shiftIt(~led[k] ); // shift out the LED array (inverted)*
* shiftIt(row ); // shift out row binary number*

* // Close the latch, sending the data in the registers out to the matrix*
* digitalWrite(latchPin, HIGH);*
* row = row << 1; // bitshift left*
* }*
}
void shiftIt(byte dataOut) { ?? Shift out 8 bits LSB first, on rising edge of clock
* boolean pinState;*
* digitalWrite(dataPin, LOW); //clear shift register read for sending data*

* for (int i=0; i<8; i++) { //for each bit in dataOut send out a bit*
* digitalWrite(clockPin, LOW); //set clockPin to LOW prior to sending bit*

* // if the value of DataOut and (logical AND) a bitmask*
* // are true, set pinState to 1 (HIGH)*
* if ( dataOut & (1<<i) ) {*
* pinState = HIGH;*
* }*
* else {*
* pinState = LOW;*
* }*
* //sets datPin to HIGH or LOW depending on pinState*
* digitalWrite(dataPin, pinState);*
* digitalWrite(clockPin, HIGH); //send bit out on rising edge of the clock*
* digitalWrite(dataPin, LOW);*
* }*
digitalWrite(clockPin, LOW); //stop shifting
}
This is the error that I am having trouble understanding:
project19.ino: In function ‘void setup()’:
project19:23: error: ‘Timer1’ was not declared in this scope
Thanks,
Don

There are two stickies at the top of the forum. Either you didn't read them, or you thought that they didn't apply to you. You should have, and they do.

Come on back after you've read them. I'm sure that you'll know what to do when you come back. If not, here's a hint. I'm positive that the code on your Arduino does NOT look like what you posted.

My guess: you didn't install the TimerOne library.