The book goes by many names:
Book of the All-Virtuous Wisdom of Jesus ben Sira
The Wisdom of Sirach
Proverbs of Sirach
Ecclesiasticus (not to be confused with Ecclesiastes, which was originally called Qoheleth.)
This last name, Ecclesiasticus, comes from the Latin word for "Church" and came about because the book was so often read in the early church. Thus, it is a misnomer for Protestants because they do not accept it as authoritative.
I finished reading it recently, and there are two major points to be drawn from it.
First, Sirach gives some window into the Jewish conceptualization of "Wisdom," which took on a meaning far more intricate than what we generally mean by the term. The Jews often anthropomorphized Wisdom. It is described as God's "first creation," begotten before all worlds. Note that these references are not just the Apocrypha, check out Proverbs 8 (and Proverbs 8:22 and Proverbs 8:30 in particular).
Sirach 24 begins
1 Wisdom sings her own praises,
before her own people she proclaims her glory;
2 In the assembly of the Most High she opens her mouth,
in the presence of his hosts she declares her worth:
3 “From the mouth of the Most High I came forth,
and mistlike covered the earth.
4 In the highest heavens did I dwell,
my throne on a pillar of cloud.
5 The vault of heaven I compassed alone,
through the deep abyss I wandered.
6 Over waves of the sea, over all the land,
over every people and nation I held sway.
7 Among all these I sought a resting place;
in whose inheritance should I abide?
8 “Then the Creator of all gave me his command,
and he who formed me chose the spot for my tent,
Saying, ‘In Jacob make your dwelling,
in Israel your inheritance.’
9 Before all ages, in the beginning, he created me,
and through all ages I shall not cease to be.
10 In the holy tent I ministered before him,
and in Zion I fixed my abode.
11 Thus in the chosen city he has given me rest,
in Jerusalem is my domain.
There was a deep connection that equated (or intrinsically linked) Torah with Wisdom running through much of Jewish thought. I think there is much to be understood by studying these connections because they appear to match the incarnation of Jesus as Living Torah that provides Wisdom (the Holy Spirit). In Chapter 9 of TGYNH I wrote about the relevance of Jesus as living Torah for the Jew/Gentile issues in the early church.
The second important point to draw from Sirach is that it paints an empty picture of the afterlife. There is no post-death reward, no resurrection, no Judgment, etc. Sirach presents the interesting notion that God's justice is seen in how we die and how we are remembered. The wise and righteous do not have a painful death, are remembered by many after they are dead, and generally have lots of prosperous offspring. The ungodly may suffer greatly at the end of their days, perhaps just in the last day, and will not have a positive posterity.
This is quite an interesting way to grapple with the crises of faith the Jews of Sirach's day encountered. They had been dominated by ungodly nations and many righteous Jews (among a generally unrighteous nation) had suffered early death. Furthermore, those who oppressed the poor seemed to live a good life. Where is God's justice then? For Sirach, the key was that one could never know what pain someone might endure in their final hours, so one could never claim that someone profited from evil.
More important than Sirach's view of God's justice is the simple fact that Sirach lived relatively late, only a couple hundred years before Christ, yet even then the notion of an active afterlife appears not to have been the norm.
For me this is important because people are often taught the great fiction that all Hebrews who came before Jesus were looking forward to a savior who would save them from hell, when in reality the Hebrews did not even believe in an active afterlife until a couple centuries prior to Jesus, let alone the notion that we are all in need of deliverance from a wrathful God who judges everyone based on a strict law demanding absolute perfection.