Most likely this text was simply Ted strategizing how to best deliver his fourth bomb. But, there are a few other theories, including that he wrote this text primarily with a mind to being able to secretly share it with some other anti-tech extremists as a guide:

Furthermore, while it is clear that Kaczynski plotted and carried out his crimes alone, he also contemplated recruiting others to join in his plans. Among the many documents found in his cabin were "how to" guides he had prepared -- a handwritten manual recounting step by step how to construct improvised bombs with detailed instructions on how to avoid detection by the FBI or police and a handwritten document entitled "How to Hit an Exxon Exec" detailing with chilling precision the step by step process one can undertake to send a package bomb to a corporate official. Ex.92. There were also copies of correspondence sent to other organizations, such as letters to radical environmental groups "Earth First!" and "Live Wild or Die", offering secret codes for communicating and seeking an audience for his "strategy for revolutionaries seeking to destroy the industrial system."

A more far fetched theory is that the text was written to potentially send directly to the FBI along with misinformation about himself. The reason would be in hopes of getting the FBI to focus on chasing down fake leads due to putting mistaken confidence in the newest drawing and description of the Unabomber e.g. that the Unabomber had reddish-blond hair.

Evidence for this theory is that this paragraph below was archived with the text, and marked C-263, so they may have been found together. Also, that he had attempted many other misleads over the course of his bombings:

Send to Abigail Van Bureau a letter from a woman who states she discovered that her husband is a member of F.C. She says she does not want to turn her husband in. She will confirm the published description of the suspect.

It appears Ted was so confident the sketch and description of the Unabomber was so far off, that he contemplated ways to make the FBI even more confident in their mistaken beliefs as to what he looked like.

KACZYNSKI: According to the witness’ description, the Unabomber had reddish blond hair, and this was massive. This description was massively publicized, according to which the Unabomber had reddish blond hair. It’s obviously inconvenient [for the FBI] that my hair is brown instead of blond.

Finally, here's the simplest explanation as discussed at the beginning:

4. Percy Wood Bomb (#4)

On June 10, 1980, Percy Wood, then the president of United Airlines, opened a package which he had received in the mail the previous day. The package was postmarked from Chicago and contained $1.40 in postage include one $1.00 "America's Light Fueled By Truth and Reason" stamp. On the mailing label, the words "Parcel Post" and "Contents merchandise" were crossed out and replaced with "Book rate". Approximately a week before Wood had received a letter from "Enoch Fischer" stating that he would be sending Wood a book entitled Ice Brothers by Sloan Wilson which "Fischer" stated was "a book that should be read by all who make important decisions affecting the public welfare". When Wood opened the package which he had received in the mail he found the expected Ice Brothers. When he opened the cover of the book, however, it exploded.

In a coded passage dated August 18, 1980, the defendant states, in part:


In the remainder of the passage, the defendant notes that the device failed to perform as desired and speculates about the cause of the failure. In another partially coded entry dated September 15, 1980, the defendant expresses his anger over jet noise and states:

After complicated preparation I succeeded in INJURING THE PRES. OF UNITED A.L. BUT HE WAS ONLY ONE OF A VAST ARMY OF PEEPLE WHO directly and indirectly are responsible for the JETS.

Searchers also found in the cabin a handwritten document entitled: "How to hit an Exxon Exec" which discussed sending a book-like package to the target's home preceded by a letter.

And finally the text itself

How to hit an Exxon exec:

Send book-like package -> to his home preceded by a letter saying I am sending him a book I’ve written on oil-related environmental concerns attacking environmental position—and I’d like to have his comments on it before preparing a final version of manuscript.

Also put in the letter a disclaimer stating that the book represents my own personal views and not those of the company I work for. This gives a touch of realism and it also explains why the letter is not on the company’s letterhead.

For return address: Get names and addresses of several big-time business execs and call direct [unreadable] to get their numbers, until you hit one who has an unlisted number. Use his return address. Thus you’ll have a real return address, but the Exxon exec can’t get his number to call for verification.

OR — send package with return address of (an oil?) exploration firm.

Also, put in the letter a disclaimer stating that the book represents my own personal views and not those of the company I work for. This give [sic.] a touch of realism, and it also explains why the letter is not on the company letterhead. (But try to Fake private letterhead.)