Signal Integrity

what is Signal Integrity?

Here is a good "paper":http://www.csee.umbc.edu/csee/research/vlsi/reports/si_chapter.pdf by Raymond Y. Chen. He states:

bq). The term Signal Integrity (SI) addresses two concerns in the electrical design aspects – the timing and the quality of the signal. Does the signal reach its destination when it is supposed to? And also, when it gets there, is it in good condition? The goal of signal integrity analysis is to ensure reliable high-speed data transmission.

Thanks for your response & valuable time.