Strategic Logic is one of the best books I've read in a long time. I'd compare it to Greenwald's Competition Demystified in terms of both subject matter and quality. I would say it is extremely useful for two specific groups: value investors and entrepreneurs.
The book is about identifying and exploiting competitive advantages. An insight it brings is its focus on a company's activities (rather than the company as a whole) in ascertaining where an advantage may lie.
The book's ideas are drawn from the simple premise that only where an advantage is present (and possible advantages are discussed in detail) can profitability be maintained above the cost of capital. But from this simple notion, some powerful strategic ideas can be drawn.
Jarillo provides examples, both theoretical as well as through public companies, of how companies can grow both within their markets and without, whether geographically or through new product introductions. Jarillo discusses when strategic acquisitions may make sense, and when they likely to end in value destruction.
In general, I don't like to re-read books; but I will probably make an exception for this one sometime in the future.