How can I publish text and video without revealing my identity?

This is an extremely broad question and it depends on many factors. You'll need to adopt a pen name. This name must have no relationship to your name or your interests. If you like video games, you must not use a Mario reference, for example. Do not interact with your pen name either. That is, do not even mention that you (the real and public you) know that the book exists. This is called OPSEC.

You might want to manage the videos and publish the book while using the Tails live DVD.

Anonymously publishing a book

Avoiding attribution with the book requires you pend special attention to resist stylometric attacks. There are dozens of research papers on how to do this, as well as tools to assist with it. The general idea behind stylometry is that everyone has a unique writeprint, and with sufficient text, it's possible to uniquely identify individuals. It's a very powerful technique using multiple methods and can accurately identify if two texts are from the same individual in a set of nearly a million. Avoiding it requires adhering to strict writing rules. Stylometry is a bigger deal if your adversaries are sophisticated.

If your neighbors, co-workers, etc. have access to a large number of "sample" texts from you, they will be able to use simple and public tools to determine how likely it is that this book was written by you. I do not know how sophisticated they are or how dedicated they are into proving authorship.

Anonymously publishing a video

It's more difficult to hide your identity when creating a video. If you expect any level of sophistication behind those who want to identify you, you need to use a throwaway camera. The reason for this is that every camera lens and CCD sensors have unique artifacts that may not be visible to the naked eye. These artifacts can prove with absolute certainty that two videos come from the same camera. Other than that, it really depends on what the video will be of. You'll need to avoid having anything that can identify you in the background, for example. It's also vital to strip EXIF data, if present.

Protecting the identities of your readers

Unless someone is purposefully trying to remain anonymous, they are going to be identified. You can perform the most basic privacy measures like hosting the video on a site which does not keep or publish logs and using a distributor who does not require personal information. Even then, you must expect some of your readers will talk about your book with their real name on social media.

At the extreme end, you can publish the material through a Tor hidden service. This is a special domain which can only be accessed over the Tor anonymity network. Naturally this will alienate some readers, as not everyone will be willing to download a new browser just to read your book, but it will guarantee that, by default, everyone who views the material will leave no trace of doing so on their computer or in their ISP logs. Obviously, this doesn't prevent someone from disclosing that they read your book...

"co-workers, employers, and neighbors"

I agree with all the advice given so far in comments and answers, but felt this deserved some more specific advice around your stated adversaries.

Establishing an alter ego

For your purpose, you don't need an entire false identity, just some anonymity. I would suggest using a free, privacy-focused email service (ProtonMail would probably be a good choice, though there are others). You probably don't need an anonymous phone number unless you intend to deal anonymously with publishers or other business partners you don't trust, and you should avoid voice interactions at all costs anyway.

Obviously, don't make your alter ego's identity linkable to yours. For example, if you spent your 20s drinking red wine and telling everybody that Kafka was the greatest mind of literary history, then don't go naming your alter ego Franz, or Gregor, or Joseph, or Valli, Elli, or Ottla, etc. Likewise, no dead pets or beloved high school teachers that your internet history might reveal. I'd use one of the countless name generators available online for creating RPG characters, or something like that.

Pseudonymous self-publishing isn't really that hard if you aren't concerned about subpoenas or law enforcement investigations. With your new email address you can create a free site (WordPress.com would be fine for this) and video hosting account. To preserve your visitors' anonymity you might choose to avoid YouTube — Dailymotion would be fine, or take your pick.

If it were me I would take some basic precautions while operating my alter ego — for example, I would install a browser separate from the one(s) I currently use to create and sign into those accounts, and perhaps use a VPN while creating and operating them (though really, that's probably overkill, as the adversaries you're concerned about are not going to have those kinds of resources anyway).

Protecting your readers' identities

As noted in other answers, there's only so much you can do here. So long as your book and videos are on a platform which doesn't require anybody to sign in (all those mentioned above would be suitable) that's probably as much as you can reasonably do. If you were really dedicated, and had the time and skills, you could always set up your own server to host everything, configure it to be logless, only accessible through Tor, etc. But that really changes your attack surface, as your own self-administered server is much more likely to be vulnerable to a curious attacker interested in deanonymising you than the above-mentioned widely-used free services. That is, I think, a bad tradeoff.

Maintaining your pseudonymity

As already mentioned by others, there are some simple OPSEC precautions you will need to take. Most importantly, your real identity cannot have any interactions with your pseudonym, at all. "You" have no knowledge nor awareness of the book, site, or author, don't mention it, and don't appear interested if anybody else does.

Use only your alter ego and pseudonymous details when promoting, discussing, or corresponding about the book, videos, or any other detail about the publication. Don't do anything by voice, obviously. If you are concerned about the stylistic analyses described in some answers and comments here, then keep correspondence from your alter ego to an absolute minimum.

Unless you become the target of a dedicated, experienced investigator or hacker, these simple precautions should be more than adequate for your needs. A lot of people self-publish pseudonymously for all sorts of legitimate reasons, and most take less care than is outlined here without real risk.