Can't comment yet, but: There are two questions. The guidelines suggest focusing on one question. I'll try to answer, anyway, for the reputation.
That example sounds like the abstract of a research paper, in fact a book .
I deem the style rather colloquial (e.g. "we try", "good idea"), which is common for researchers who are not primarily linguists, I dare to say. Although, "in which" is aimed at a formal tone. (I doubt it's a parody, more like tradition or homage).
To start with "In which" draws a connection to the matter of the title. Here, it means as much as "here" ("in" denotes direction). This usage is highly idiomatic, because "which" normally introduces a subordinate clause, not a substantive clause. Comparison to "wherein" suggests we are dealing with an adverb, hence an adverbial clause.
The latter subordinate clause "this being a good idea" is superfluous, because we expect to be presented with positive work. However, repetition is a valid stylistic device.
Subordinate clauses don't require a verb. "being" is used as participle , so "is" is not directly an alternative. That construction is called Participle Clause and, because of the weak noun "this", Nominative Absolute . Using "is" is possible, but it would turn the sub clause into a main clause, or require a connective like "because". Frankly, it's a contraction to keep the text shorter.
 Russel & Norvig: Introduction to AI: A Modern Approach
I don't think I understand this sentence completely
That's what English Language Learners SE is for; which is probably why perfectly good answers are posted as comments instead.